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Dual Cores Taken for a Spin in Multitasking

Posted by CowboyNeal on from the burn-up-testing dept.

Vigile writes "While dual cores are just now starting to hit the scene from processor vendors, PC Perspective has taken the first offering from Intel, the Extreme Edition 840, through the paces in single- and multi-tasking environments. It seems that those two cores can make quite a difference if you have as many applications open and working as the author does in the test." It's worth noting that each scenario consists of only desktop applications, and it'd still be interesting to see some common server benchmarks, such as a database or web server.

47 of 221 comments (clear)

  1. Newsflash... by jawtheshark · · Score: 5, Funny
    SMP system performs better when applications are multithreaded...

    (Dual core is the same as an SMP system, except the cores can communicate a bit faster with each other)

    --
    Ahhh...the great dumpster continuum. Many a free computer will be found there. -- sowth (748135)
    1. Re:Newsflash... by beezly · · Score: 4, Insightful

      That is not necessarily true.

      I know this article is talking about Intel dual core chips, but for well-designed CPUs with integrated memory controllers (Power5, Ultrasparc IV, Opteron), the difference between a single dual-core CPU and two single-core CPUs is significant.

      On chips with built in memory controllers, as you increase the number of cores on a chip the memory bandwidth per core decreases, however as you increase the number of chips in a system, the memory bandwidth per core remains the same and the number of cores increases.

      That can amount to a big performance difference when running memory-intensive jobs.

      Intel seem to be really losing the plot here at the moment. In multichip configurations, Intel's memory bandwidth already sucks compared to Opteron. Multicore per chip is only going to make it FAR worse.

    2. Re:Newsflash... by The+New+Andy · · Score: 5, Informative
      ... assuming the OS chooses which threads are executed on which core well enough. If two threads depend on each other heavily and they are running on different cores, you can get really crappy performance.

      So the obvious answer would be to move one of the processes to the other core. However, this isn't trivial. You either have one scheduler per core or one scheduler per operating system. (You can't have a single thread sent to both cores easily - if both cores run the same thing at the same time there will be chaos)

      If you have one per core, then the scheduler trying to get rid of the thread will have to synchronise with the other core, waiting for the other scheduler to come into context, it then has to tell it to add this new process. Obviously, there is a fair bit of overhead, and if my memory serves me correctly, each core in the current chip has its own cache - so now all the stuff which was cached has to be sent to memory (since it is in the wrong cache) and now there is nothing in the cache, making every memory access slow for the next little while. End result - you can transfer a thread between CPUs, but it is costly.

      It is possible to have a single scheduler which can then just dispatch threads to each core as it gets run by each core. The big one here is making the scheduler threadsafe - both CPUs could run the scheduler at the same time, so you have to make sure they don't crap on each other. This is a problem which we have solved already with common synchro-primitives. But, if you just lock the list of threads to run (*), then you will get a whole lot of CPU time wasted just waiting to run the scheduler. It might be acceptable for 2 cores, but it doesn't scale at all.

      (*) You may realise (just as I realised) that a scheduler is more than just a list of threads to run (it is typically implemented as a couple of lists for each priority). The same problem still occurs with more than one list of threads, it is just a bit harder for me to express (proof by bad English skills).

      Finally, I'm expecting someone to tell me that I'm wrong about something I just said. That person is probably correct. My only experience with this stuff is a 3rd year undergrad operating systems course where we played around with OS161 (a toy operating system basically). But, hopefully the end conclusion will be the same: twice the number of processors won't equal twice as much performance, and it is tough to get a fast algorithm that will scale.

    3. Re:Newsflash... by hyc · · Score: 2, Informative

      The fact is, when you have only one problem to solve, a single fast CPU is always better than an equivalent count of slower CPUs. One 1GHz CPU is better than 2 512MHz CPUs of the same design, for solving a single problem.

      It's another fact that it's easiest for humans to analyze only one problem at a time. So the most straightforward way to handle any computing task it to crunch at it linearly from beginning to end.

      Unfortunately, gains in raw CPU speed have always come slower than the demand for number-crunching power, which is why there have been so many parallel supercomputer designs over the past couple decades. And again unfortunately, the only way to get good performance out of those designs is by explicitly coding for parallel processing. And that's hard for humans.

      The bottom line is that when you throw two 1GHz processors at a problem, your time to solution is not twice as fast as using one 1GHz processor. There are overhead costs associated with reallocating the problem and managing the increased number of processors. But, it *is* still faster than using one 1 GHz processor.

      Scale the numbers up as appropriate.

      Still, it was fun watching the blinking lights on our Connection Machine, a decade or so ago...

      --
      -- *My* journal is more interesting than *yours*...
    4. Re:Newsflash... by jawtheshark · · Score: 3, Insightful
      when you have only one problem to solve

      That highly depends on the problem. If your problem is highly parallizable and the application that resolves your problem has been written (correctly) in a multithreaded way, then two CPU's will perform better. (As you say, it doesn't scale in a linear way)

      Of course, you might just say that a parallizable problem is not one problem, but many small problems that need to be solved separately ;-)

      --
      Ahhh...the great dumpster continuum. Many a free computer will be found there. -- sowth (748135)
    5. Re:Newsflash... by Senor_Programmer · · Score: 2, Insightful

      Is it just me or did the performance of the single core AMD relative to the Intel dual core in those benchmarks just scream out..."I want the AMD dual core!"?

      Seriously, unless you're application can run in the cache on the Intel parts, the AMD is gonna win hands down when running at the same clock rate which translates pretty closely to the same power consumption. AMD will yet be a tad lighter on power consumption just because the stuff is packed more tightly even though it has more active components. Equal 'wire' size + smaller size = shorter 'wires' resulting in reduced IR losses (for the same operating voltage).

    6. Re:Newsflash... by walt-sjc · · Score: 2, Insightful

      While that's true, these dual core chips (especially Intel's lame single-memory bus design) really seem targeted towards the desktop market where the impact is greatest, yet cost differential is realativly small (in relation to the total price of a system including software.)

      I'm more interested in what IBM's Cell processor can do. While some problems are definately single threaded by nature, the majority are not. I have a GIS application that could definately benefit from as many processors as I can throw at it (although there comes a point where you need more memory, disk I/O etc. too so you still need to spread them out over a cluster to some degree.)

    7. Re:Newsflash... by beezly · · Score: 2, Interesting

      Dual Bus memory still doesn't cut it.

      Each Opteron has a dual bus memory controller on board (granted, only DDR400)... but as I increase the number of CPUs, the number of memory busses increases.

      The 4 CPU boxes I'm working on have 8 independent DDR400 memory busses.

      The only obvious way to get your memory bandwidth to scale is to have your memory controllers per CPU (or even better, on the CPU itself).

    8. Re:Newsflash... by MuMart · · Score: 2, Insightful
      On chips with built in memory controllers, as you increase the number of cores on a chip the memory bandwidth per core decreases, however as you increase the number of chips in a system, the memory bandwidth per core remains the same and the number of cores increases.

      Even in a multi-memory controller system the same physical memory is shared, so there has to be some performance hit when running more than one cpu, so I doubt the actual memory bandwidth per chip will be the same. Or is there some architectural trick that removes that bottleneck in practice?

    9. Re:Newsflash... by beezly · · Score: 2, Informative

      That's NUMA - if your OS is NUMA aware it should try to place processes on the same processor as the memory that contains their data.

      But yes, you're right, processes accessing memory on a different processor will suffer a latency (and to some extent bandwidth) hit. A well designed OS will help to mitigate it to some of the extent, but it's one of the reason that CPUs don't scale linearly.

    10. Re:Newsflash... by dascandy · · Score: 4, Informative

      Actually, the opposite. Two processes that communicate quite heavily SHOULD be run together on two processors, especially since they will share memory and thus cache lines, plus they can spend time spinning on a lock instead of swapping threads. Given short locks and equal speed, they can work a whole lot more efficient on a dual-core than on a single-core.

      FYI, it's called Gang Scheduling and has been described for quite some time.

  2. A matter of time. by Renraku · · Score: 5, Insightful

    How long before applications start figuring that they should have an entire core dedicated to them?

    Windows, for example. What if the next version of Windows requires a dual-core processor to be usable? You know..Windows gets one core to idle at 80% of its capacity..and spills over into the other core when loading a text file.

    If things stayed the way they were now, and the entire other core could be kept separate from the OS and used for gaming/other applications, it would be a great idea.

    But guess what.

    --
    Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
    1. Re:A matter of time. by jtshaw · · Score: 3, Insightful

      That would be a total waste of CPU time.

      Very few applications, and OS's in particular, are idle most of the time. I don't know the exact profiling characteristics of Windows, but I do know that in linux the kernel rarely, if ever, takes up 100% of a CPU's, and never does for a prolonged period of time.

      If you locked one CPU and made that for OS tasks only you'd be wasting a lot of clock cycles that another application could happily use. Same would go for locking just about any application to a cpu.

  3. Well... by X0563511 · · Score: 4, Interesting

    I'm still bumming around with a sub-gigahertz chip, specifically an Athlon T-Bird. I've been out of the loop for too long, can anyone tell me the benifits of using a dual core system (and while we are at it, a 64-bit chip)? Any problems to look out for if I decide to jump on the wagon in my next upgrade?

    --
    For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
    1. Re:Well... by FidelCatsro · · Score: 2, Informative

      For the average user , if i were to be totaly honest. Right now there is hardly any real use for either. Duel cores would probably help the system apear faster if the average user is switching around alot of programs ubt for the price you would pay then it is not worth your time.

      64-bit well um if the average user um well runs a massive database setup but it will be more usefull soon in the x86 world (athlon 64 procesors though are excelent because of the onboard memory controler and architecture).

      For the power user , well i don't think we need to explain this to the power users, In a server enviroment duel core and 64-bit computing is wonderfull for many many reasons also in workstations for many many enginering jobs.

      --
      The only things certain in war are Propaganda and Death. You can never be sure which is which though
    2. Re:Well... by shyampandit · · Score: 2, Informative

      Mainly the difference would be found when running many apps at once. For example if you are ripping songs and playing a game simulataneously then it would be faster than a single core machine. I run many programs like proxy servers, mail servers etc. for the home LAN and also use it for games. So in this situation dual core will help me run the game lag free.

      Although for the speed boost to materialize in games they will have to be coded to use both cores, so one dosent just idle away.. When more programs get SMP aware then dual core would be great!

      The only problem righ now is, single core procs like amd64's can beat the crap out of dual core when tested mainly in single app environments because they have a higher clock speed.

    3. Re:Well... by tomstdenis · · Score: 4, Informative

      AMD64 carries more than just "bigger registers". It has more of them and the actual core is an overall improved K7 process with

      - Slightly longer scheduling buffers
      - 128-bit L1 cache bus
      - Larger instruction window (means it can feed the alus better when constants/etc are found)
      - more registers [and they're bigger]

      They also run cooler and takes less power than their k7 brothers.

      Tom

      --
      Someday, I'll have a real sig.
    4. Re:Well... by JollyFinn · · Score: 4, Informative

      The 64bit is for anyone with more than 2Gb of RAM + x86-64 gives you more registers besides being 64bit so it speeds up the recompiled code.

      Dual core means simply you have TWO processors running. Rember old reviews on SMP dual celeron A and other such reviews. It gives little for games, lots for certain multithreaded applications. As you have two processors running and doing things. And multitasking applications, like being able to run interactive application (doom 3), while system is doing some multihour compilation on background.
      Anyway, it mainly keeps system more responsive when you have some thread or application takes CPU.
      Also with lesser degree helps in some other similar situation, where CPU is tied up with something EXACLY same moment you would wan't it to deal with UI stuff.

      --
      Emacs is good operating system, but it has one flaw: Its text editor could be better.
    5. Re:Well... by tomstdenis · · Score: 4, Informative

      .... Me work for AMD? Ha!

      No, I'm just a happy loyal user. I have both a Prescott P4 3.2Ghz and an AMD64 Newcastle 2.2Ghz...

      For what I do [building software] the AMD64 smokes the P4 ... and does it without getting to 50C or so...

      The AMD approach is just common sense. Be more efficient at what you do and gradually do it faster. Intel went the market route and said "slow clockrate is for pansies!".

      So you end up with a cpu that has a higher clock rate but it doesn't win because the efficency is too low.

      AES on my AMD64 ranges around 260 [or so] cycles/block. On the P4 with Intels compiler I get around 410 cycles/block. If you scale 3.2Ghz to 2.2 Ghz that's still effectively 281 cycles [at 2.2Ghz]. Doesn't seem like much but keep in mind to get this speed they had to draw more power and run at a higher clock rate.

      I did a benchmark a week ago where I built LibTomCrypt with/without hyperthreading and it took the prescott with hyperthreading at 3.2Ghz to even come close to matching the AMD64 speed. That's only on ~45,000 lines of code.

      Now multiply that by say five or ten to get a larger project.

      I'm not saying the Prescott isn't a neat design. Overall it's efficient enough to be useful. Just the AMD64 eats it's breakfast and spanks it's mother is all I'm saying. ;-)

      Tom

      --
      Someday, I'll have a real sig.
    6. Re:Well... by Karaman · · Score: 2, Informative


      Hi, my older PC was a T-Bird@850Mhz with 256 RAM, 160GB HDD- PATA133 (CPU was working at 50 deg C)

      Now I have Athlon64 3000+ (233x8 = 2000MHz) (s939) with 1GB RAM, 200GB HDD- SATA150 (CPU does not go beyond 37 deg C)

      The difference is that with the older pc I compiled and installed LinuxFromScratch in 4 days (well I drank a lot of caffeine products),
      while when I switched to the A64 PC I did the job IN ONLY 4 Hours!

      Unfortunately I was unable to compile a stable x86_64 toolchain to complile a x86_64 Linux and now I have i386/i686 GNU Linux but hell it is fast and I love it!

      --
      sex is better than war!
  4. Well? by Anonymous Coward · · Score: 5, Funny

    Does this mean my Windows XP machine wont pause when I put in a floppy or Cdrom? Wow, sign me up.

    1. Re:Well? by EpsCylonB · · Score: 4, Funny

      no but it will make your internet faster.

    2. Re:Well? by MattHaffner · · Score: 2, Funny

      Internets, you mean. Multi-core and all...

    3. Re:Well? by kabocox · · Score: 2, Funny

      Does this mean my Windows XP machine wont pause when I put in a floppy or Cdrom? Wow, sign me up.

      Nope, that feature isn't scheduled until after we have 16 cores on chip, 32 Gb of RAM, 10 Terabytes of HD storage, and optical media is at 1 Terabyte per disc. They said it was a wierd hardware limit and it would require at least that much processing power for Windows XP to read a floppy or CDROM and do anything else. You don't even want to know what it will take for Longhorn to do that.

  5. Something missing by FidelCatsro · · Score: 4, Interesting

    What this test really was missing was a direct comparison to SMP systems which really for me makes the results entierly boring and expected .
    If he had shoved in a duel opteron set-up and a duel xeon set-up then it may have been a little more intresting , though as it stands its like stating the obvious.

    --
    The only things certain in war are Propaganda and Death. You can never be sure which is which though
  6. Anandtech by iamthemoog · · Score: 5, Informative

    Has the new dual core opteron up against a quad Xeon with 8MB cache, amongst many others.

    Well worth a read:

    http://www.anandtech.com/cpuchipsets/showdoc.aspx? i=2397

    --
    No Norm, those are your safety glasses; I'll wear my own thanks...
    1. Re:Anandtech by astro-g · · Score: 2, Informative

      I love how he says the only difference between the 8xx operons and the 1xx opterons is the ammount of validation testing each chip gets.

      Umm, what about the number of available HT channels?
      There is a reason you cant use the 1xx chips in the 8 was motherboard.

  7. Re:Fundamental question about dual core by rodac · · Score: 2, Insightful

    In general and assuming a non broken cache architecture, a 2CPU/core solution will feel faster than a single cpu solution with twice the cpu frequency.
    The total number of cpy cycles are the same, but the average queue-length for a process waiting for the CPU is half, i.e. the latency before your process is scheduled is lower making it "feel" faster.

  8. One thought I had... by Kjella · · Score: 4, Interesting

    ...and I'm not quite sure if it's a good one, but for desktops:

    The foreground program has a dedicated core. If you switch programs, put the old on the "other" core. The new moved from the "other" core. Essentially, your current program has full responsiveness (assuming you don't do things that lock up the application itself), no context switches, no other programs that can run some weird blocking call (on a single core machine, it certainly looks that way at least, especially CD-ROM operations).

    Granted you could end up with your fg processor being idle most of the time. But the way many people work with the computer, the foreground program is the ONLY time-critical application.

    Kjella

    --
    Live today, because you never know what tomorrow brings
  9. Will my Spyware support these? by Anonymous Coward · · Score: 2, Funny

    Or do I have to wait for Service Pack 3?

    Yours,

    Gator Fan.

  10. Sluuuurp..... by Diakoneo · · Score: 3, Interesting

    That last page raised my eyebrows. 291 Watts under load, that's some serious power draw compared to what I'm used to. And that had to be kicking out some serious heat, too.
    Anybody know what is the draw for a 4x Xeon system? I'd be interested in seeing how they compare.
    I wonder at what point the facilities people will want to use the server farm to heat the building, too. A weird convergence, the PC world is becoming more like the old mainframe world.

    --
    "Well..here I am..." - Jubal Early
  11. How 'bout some Adobe CS benchmarks? by Aqua+OS+X · · Score: 4, Insightful

    Who the hell runs benchmarks with FireFox and iTunes.

    if you ask me, the people that desperately need the ability to multitask are folks in the creative industry. Every 5 minutes bounce back and forth between massive applications rendering huge files.

    Nothing sucks more then opening a 400dpi photoshop document and not having InDesign respond since your single core CPU is being bogarted.

    SMP is probably the only reason I still find my crusty old Dual 450 g4 useful. It does things slowly, but it doesn't "feel" slow. If something is taking its sweet ass time, I can usually do something else without waiting years for windows and menus to draw.

    --
    "Things are more moderner than before- bigger, and yet smaller- it's computers-- San Dimas High School football RULES!"
    1. Re:How 'bout some Adobe CS benchmarks? by Jameth · · Score: 3, Funny

      You're dead on accurate with that one. I want a benchmark that will tell me what kind of performance I can expect if I have a logo I am editing in Illustrator that I open in Photoshop to clean up a bit and then insert into a document in InDesign while I'm trying to make it look similar in the webpage I'm putting together in TextPad, viewing both final documents through Acrobat, IE, FireFox, and Safari, all at the same time. (While listening to music.)

      And no, I'm not being sarcastic. Although I rarely do all of that at once, it has been known to happen. And don't even get me started about what happens when I have something compiling behind all of that. I'm just thankful, in a way, that since I don't do 3D work I'm not tossing Maya into that mix.

    2. Re:How 'bout some Adobe CS benchmarks? by archen · · Score: 2, Informative

      Firefox might not be such a bad benchmark. Go a bunch of Japanese pages with status bar scrollers (in japanese) then open up about 20+ tabs. I do this every day, and the CPU usage on Linux can go up to a sustained 70-90% or more. If gcc is working in the background, the system can really lack responsiveness (and I'm on an AthonXP 3000 with 1Gb of RAM). Out of all the apps I use, Firefox and Mame take the cake in CPU usage.

  12. shared FSB (intel) or not (AMD); other benchmarks by coats · · Score: 4, Informative
    After reading the article, I realised that the frontside bus was shared. I didn't expect that. It seems to be a transitory solution in order to have the "first dual-core" CPUs on the market. When AMD releases theirs I expect them to have a superior solution.
    AMD64 has had the circuitry for dual-core on-chip memory controllers from the very first -- they just didn't have the second CPU core. For a good discussion of the differences, see http://www.linuxhardware.org/features/05/04/21/174 7217.shtml at LinuxHardware.

    For benchmarks relating to serious DB and web use, see this review by Anand Shempi: http://www.anandtech.com/cpuchipsets/showdoc.aspx? i=2397 or these two at FiringSquad: http://www.firingsquad.com/hardware/amd_dual-core_ opteron_875/ and http://www.firingsquad.com/hardware/colfax_dual_op teron/

    --
    "My opinions are my own, and I've got *lots* of them!"
  13. Re:shared FSB (intel) or not (AMD); other benchmar by dchallender · · Score: 3, Informative

    Extremetech have a review of AMD opteron dual core http://www.extremetech.com/article2/0,1558,1788685 ,00.asp?kc=ETRSS02129TX1K0000532

  14. Comment removed by account_deleted · · Score: 2, Informative

    Comment removed based on user account deletion

  15. It's bad news, actually... by pmadden · · Score: 5, Insightful

    I'll probably get flamed for this....

    Increased performance in CPUs has normally come from faster clock rates and more complex circuitry. As we all know, Intel (and the others) have bailed out on faster clocks. If you add more complex circuitry, the logic delay increases--to keep the clock rate up, you have to burn power.

    What does this mean? The old-fashioned ways of getting more performance are dead--if you try it, the chip will burn up. It's easier to build two 1X MIP cores than one 2X MIP core. Like it or not, dual cores are the only solution; with transistor scaling, we'll have to go to 4, 8, and 16 cores in the next few years. IBM went dual-core with the PowerPC in 2001. Intel, AMD, and Sun are just following suit.

    Not bummed out yet? Massive parallelism works well for people doing scientific computing, but for the average joe, it's useless. I don't care how fast a processor is--I usually have one task that will crush it--but rarely do I have two time-critical things to worry about at the same time. In the article referenced, they had to work hard to find things that would test the dual-core features. Parallel computing and multiple cores sounds great. History buffs will know about Thinking Machines, Meiko, Kendell Square, MasPar, NCUBE, Sequent, Transputer, Parsytec, Cray, and so on.... Not a happy ending.

    So.... we can't get more single processor performance without bursting into flames. And parallel machines are only useful to a small market. IMO, it's gonna get grim. (And before anyone says new paradigm of computing to take advantage of the parallel resource, put down the crack pipe and think about it--we've been waiting for that paradigm for about 40 years. Remember occam? I thought not.)

    1. Re:It's bad news, actually... by eddy · · Score: 3, Insightful

      Yeah, actually I think this might become a big boon for gamers (such as myself). The stuff that makes games interesting to me is AI (which is a very wide field certainly, but I think of such things as finally being able to use reasoning-engines (F.E.A.R is the first game I know of that use one), better pathfinding (AI can now use focussed D* instead of cheating with A*, etc) all of which will finally get to some love and tender care.

      With only one CPU, AI was always the ugly step child. "Yeah, sure.. we can give that 10% raster..." (okay, so I'm dating myself, anyho...). Now there will finally be CPU-power available that CAN NOT EASILY BE USED FOR TRANSFORM AND RENDERING (note "easily", not "possibly").

      In short; ubiquitous dual-core CPUs will revolutionize gaming.

      --
      Belief is the currency of delusion.
    2. Re:It's bad news, actually... by Junior+J.+Junior+III · · Score: 2, Insightful

      If they can't ramp up hardware any more, the next revolution in computing will not be faster hardware, it will be cleaner, more efficient code. Personally, I think that there's a lot of potential left, if not with silicon, then with diamond wafer chips, or optical computing.

      --
      You see? You see? Your stupid minds! Stupid! Stupid!
    3. Re:It's bad news, actually... by ciroknight · · Score: 3, Interesting

      Well you're right about what you were saying, those words would arbit a good deal of flames. But everything has its place and there's a place for everything. Lemme explain.

      Clockspeed is the easiest race, if you want to think of the CPU industry as a continuous race. All you have to do to crank out a faster CPU is continually shrink the die (because smaller gates flip faster), and make sure that everything is arranged neatly on the chip. When you hit thermal walls like we are now, it's simply time to reduce the voltage, and shrink the die again.

      The only problem is, Intel's flagship for doing this now, happens to be one with a lot of baggage. The Netburst core design pretty much dictates there is to be at least two of everything, and both of them should be running all the time, especially if Hyperthreading is on. This effectively doubles your transistor count (though in reality it is less than that; there's only a single copy of bus administration, micro-op decode, etc). Keeping them on all of the time also helps jump the heat production.

      But here's a truth; their CPU clock game could still be running if they would like it to. The Pentium-M is still running extremely cool. Shrink it to a 90 micron core, use SOI, strained silicon, more of their substrata magic, and a healthy dose of SpeedStep, and you could see a Pentium-M hitting 3.5GHz clockspeeds that would put both the Athlon 64 and the Pentium 4 to shame. Sadly, to build this processor is to admit defeat with the Netburst core, and Intel's being very stubborn.

      On the other hand, I believe AMD's got some magic they haven't used yet up their sleeve. Though honestly I couldn't tell you what it is. There has to be a reason they aren't playing up the Turion more other than the fact it isn't scaling down as far as the Pentium-M can. I'm also surprised they're being so slow about ramping their clockspeeds, but this is probably just so their thermal profiles look superior to Intel's. A 3GHz Opteron could easily decimate a dual Xeon setup, but at the same time would probably produce just as much heat, and I think AMD would see that as a defeat.

      --
      "Victory means exit strategy, and it's important for the President to explain to us what the exit strategy is." G.W.Bush
    4. Re:It's bad news, actually... by shotfeel · · Score: 2, Insightful

      Interesting issues, but I disagree with you on some points.

      First, there's really nothing new about multiple cores IMO. Instead of "core" try the term "execution unit". CPUs used to have a single execution unit. Then something like an Integer Unit was added. Remember the days of math coprocessors? They soon got moved into the CPU by adding more, and more specialized, Integer Units and a Floating Point Execution Unit. Now you have CPUs that have multiple execution units, to the point of having multiple Integer and Floating Point Units, and even SIMD units.

      So then, isn't multi-core simply an easy way of doubling the number of execution units in the CPU and using the OS to handle some of the scheduling?

      I'm also not sure I agree with you on parallelism. Seems to me we've had to do a lot of work to make very parallel processes linear. For example, I want to add the numbers in column A, to the numbers in column B, and multiply them by x. We start with the first pair of numbers, add and multiply. Get the next pair, add and multiply.... Most of the stuff your computer does could be done in parallel, problem is its very hard to write general purpose software or create a general purpose CPU that can really take advantage of that parallelism.

      And whenever I see someone say something like, "Its good for high performance scientific computing", that means its good for general purpose computing too. Remember most scientific computing involves repeatedly doing simple operations on arrays of data (both large and small) -almost exactly like the type of stuff your computer does for every frame it displays on your monitor. In fact, some scientific apps have even been written to use the GPU on some video cards as a digital signal processor, because that's essentially what GPUs are/do.

    5. Re:It's bad news, actually... by loose_cannon_gamer · · Score: 2, Insightful
      Not bummed out yet? Massive parallelism works well for people doing scientific computing, but for the average joe, it's useless. I don't care how fast a processor is--I usually have one task that will crush it--but rarely do I have two time-critical things to worry about at the same time. In the article referenced, they had to work hard to find things that would test the dual-core features.

      I had a small epiphany reading a review of one of these dual cored setups that released this week. One of the reviewers (I'd link, but I don't know where) mentioned that in a benchmarking discussion with a coworker, someone mentioned that the only reason we don't do benchmarks like 'run a mega intense first-person-shooter while doing some large encoding job in the background' is because until now we couldn't...

      The point was having dual cores will let you use the computer in ways you haven't been able to before. If you continue to use a dual core machine the same way you've always used a single core machine (and we've all been well trained on what processes you can run concurrently on a multitasking operating system and which ones you'd just better not), you're not going to see a benefit.

      The real benefits will come when people start to realize what they can do with a dual core system. The OS has been able to effectively multitask for a long time now, but most people don't -- they have one application going most of the time. But now we may be able to get out of the real parallelism bottleneck -- the user -- in accomplishing work.

      I think this opens up a serious new niche in most application markets -- processes you can start and let run in the background that actually do real work without much user intervention.

      And let's not forget, having dual cores is going to make everyone's SETI scores shoot through the roof. :)

      --
      In Soviet Russia, us are belong to all your base.
  16. Dual Core CPU's by antivoid · · Score: 2, Interesting

    I feel a good use for Dual-core systems is to put the OS on one core, including all explorer.exe instances and threads.

    The operating system shoul employ a smart system of monitoring CPU usage per thread and move the high- usage threads to the other core.

    I wonder though, on a slightly different topic - heat dispersion: nobody seems to talk about it - but two cores mean twice as much heat. How the hell do they do away with the heat? It dissapointing but they might be speedstepping/downclocking the cores dynamically at peak load.

    This certain warrants discussion.

    1. Re:Dual Core CPU's by ThaReetLad · · Score: 2, Informative

      Actually several of the articles do mention heat and the answer is this. Total thermal output from the top end dual core opteron is no more than for the top end single core processor (95 watts max). This has been achieved by using more energy efficient (and slightly lower perfomance) transistor designs in certain areas. AMD appears not to be doing any thermal throttling either.

      --
      You can't win Darth. If you mod me down, I shall become more powerful than you could possibly imagine
  17. OP Misses the point by Craster · · Score: 2, Insightful
    It's worth noting that each scenario consists of only desktop applications, and it'd still be interesting to see some common server benchmarks, such as a database or web server.


    Except that this is a desktop processor, that won't be shipping in server systems. So in actual fact it's worth noting that the entire point is that each scenario consists of only desktop applications.
  18. re: Dual will cores revolutionize gaming by Stunning+Tard · · Score: 2, Interesting

    There's this interview with Tim Sweeney, the leading developer behind the Unreal 3 engine.
    They're working on a multithreaded engine for unreal 3, exciting stuff.
    Like you said, AI is a logical chunk of processing that should be on a separate thread. Other logical chunks he mentions are physics, animation updates, the renderer's scene traversal loop, sound updates, and content streaming.

    So at least one multi-threaded game engine is in the pipe. This is good because we don't really have a chicken and egg problem.

    So I agree games will improve a lot with multi-core.

    But for other apps I'm not as excited. I don't know what other apps I use regularly could be sped up with a multi-threaded rewrite. Virus scanning? Searching? Media playback? eMule? SETI? Maybe lots of apps can be sped up, but will any of them do it? In the interview I linked Tim says a multi-threaded system takes 2-3 times longer to write and test.
    I don't use most of the apps that have a lot to gain from multi-cores (Media creation apps, server apps). Maybe I'll start doing more things at once. Or maybe run a dual-head system. Maybe.
    It seems games are the only resource pig apps I've ever really run, so they're the only apps that will prompt me to upgrade to multi-core. Maybe once dual cores are common non-game developers will start to exploit them. And maybe some app will suprise me but I'm not holding my breath.

    Until then a single CPU serves my needs fine. Sometimes I come across situations where I close one app to give another a boost. Such as shutting down apps to make the game faster. With a dual core I could probably run everything, but for now I'll settle for shutting extra stuff down.
    In the future when playing a multi-threaded game on a multi-core PC I'll probably still shut down extra apps just to squeeze out the extra fps.