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Is Rambus Destined to Return?

An anonymous reader pointed us to an article running over at Tom's that talks about the world of ram and criticizes the performance of DDR. The article goes into DDR333, DDR400, and Rambus, and explains the issues at higher clockspeeds.

16 of 202 comments (clear)

  1. Rambus as a company by Jesse+Duke · · Score: 2, Insightful

    Given the bad performances of RDRAM due in large part to its insanely high latency, and Rambus' dubious business practices based mainly on trying to milk patents to leech on the entire memory industry's back, why on earth should anybody give then the opportunity to make a come-back ?

    1. Re:Rambus as a company by Glonk · · Score: 3, Insightful

      How is the parent post +4?

      He links to an obsolete article from Q3 2000 about RDRAM on the Pentium III...

      He talks about the "insanely high latency", and it's pretty obvious he's exaggerating slightly.

      RDRAM's latency, particularly with the upcoming PC1066, is far better than people give it credit for. See this AcesHardware article.

      PC1066 RDRAM latency for 128 bytes: 207 cycles
      PC800 RDRAM latency for 128 bytes: 247 cycles
      PC133 SDRAM latency for 128 bytes: 229 cycles

      Slashdot moderators: Would it kill you to check the links before going points-crazy?

  2. common sense? by Kargan · · Score: 2, Insightful

    With the exception of the shady business practices of Rambus, I don't fully understand why Intel dropped RDRAM in the first place. In every benchmark that I saw circa 7-8 months ago, the huge amount of memory bandwidth present gave Intel one of it's only advantages over the corresponding AMD CPUs.

    It couldn't have just been the prices either, because Intel obviously knows they're not going to win that race.

    Anyone?

    --
    Palaces, barricades, threats, meet promises
    1. Re:common sense? by Greg+Lindahl · · Score: 3, Insightful


      Intel had 2 reasons to bring out SDRAM based boxes:

      1) Cost. Most consumers and business desktops don't care about speed, and RDRAM costs too much extra.

      2) Speed. RDRAM looked fast because it was implemented with multiple banks. You can do the same thing with SDRAM, if you like. And that would give an apples to apples comparison.

    2. Re:common sense? by VAXman · · Score: 4, Insightful

      Speed. RDRAM looked fast because it was implemented with multiple banks. You can do the same thing with SDRAM, if you like. And that would give an apples to apples comparison.

      The whole advantage of RDRAM is high bandwidth/pin, and the fastest RDRAM has more than double bandwith/pin than the fastest DDR. RDRAM is very cheap to make dual channel because it has fewer pins. It is very expensive to make a dual channel DDR system because it requires that many more signals. The only dual channel DDR system I know of is the upcoming Serverworks Grand Champion chipset for the P4 Xeon which is very high-end (and no doubt expensive).

  3. Re:Experience tells us by Anonymous Coward · · Score: 1, Insightful

    Of course this is only relevant if speed is important to you. Right now DDR keeps up pretty well with both Athlon and P4, so if you have a fixed amount to spend it makes sense to buy a faster processor and not the fastest memory.

    But both CPUs will get much higher clock rates in the next few years, and it's not clear if DDR can keep up. If memory starts to seriously limit performance, then it will make sense to buy RDRAM. (Of course RDRAM + Athlon is not a possibility in the foreseeable future.)

  4. doesn't it depend... by ryusen · · Score: 4, Insightful

    on what systems you are working with? if you want a performance p4 system then obviously you use rambus... and if you want an amd system you use ddr(since there is no rambus/athlon chipset)
    and until there is a rambus/athlon chipset i don't really think we can gague the real world implication of it...
    either way i have better things to do with a few $100 than put it into a more expensive chipset/cpu/memory rig. if you have the extra money and the rambus system gives you what you want, then more power to you. overall, right now, you can't say either system is "the best" in ever possible catagory

    --

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  5. Re:As an small OEM computer maker, I hope not by Graymalkin · · Score: 3, Insightful

    While Rambus memory might not be the best design in the world your arguments for why it is garbage are retarded. The memory is interleved and runs hot. There's nothing wrong with interleved memory designs except the fact you have to buy two modules rather than one. If you use memory from different manufacturers in SDRAM based systems you can wind up with a system not booting too. It depends on how robust your memory controller is. They run hot but have twice the memory bandwidth of PC2100 memory. That sort of tradeoff is always inherent in a computer. You could say RDRAM is garbage because of the limited number of suppliers or patent issues or memory even the high latency. Instead you picked the fact it was interleaved and hot.

    --
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  6. Re:My time with rambus has been awesome by Chris+Burke · · Score: 4, Insightful

    Were the AMD systems Duron-based? :)

    What about games that -don't- love the P4, like, say, -any other game- (even those based on the Q3 engine)? :)

    But no one needs to do the same testing you did. They can just look at all the tech sites. Hey, you already visited Tom's Hardware to read this article, check out who -he- thinks has the "best possible performance in 3D".

    At one time, your "best possible performance in 3D gameing" applied... That time was the year 2000, and Q3A was the most demanding benchmark anyone could cook up It is now 2002, and the world has moved on from Q3A, and P4 lost that crown. But nice try.

    You should have said "media encoding", because then you'd have been right even today.

    As to AMD using Rambus... It'd suck. P4 does better with RDRAM than DDR because it's a highly pipelined, high-clocked machine that craves bandwidth. The K7 is a very wide machine, and for it the worst thing that can happen is having to stall waiting for data. The latency of RDRAM would kill the K7. You'll note that the dual-channel nforce (higher theoretical bandwidth than the i850, and 2x the KT266A) doesn't outperform VIA's chipset. An likely reason would be that the KT266A has lower latency, and that more than makes up for the extra bandwidth (which K7 doesn't need).

    --

    The enemies of Democracy are
  7. Is Intel's DDR implementation bad, or not? by landley · · Score: 4, Insightful
    The guy starts out the article saying that Intel's DDR implementation was crippled for political reasons. He also states that Athlons benefit from DDR more than P4.

    Then the political aspect is ignored and he talks almost exclusively about technical issues about why Rambus might theoretically be better, and uses existing intel chipsets as evidence.

    Hello? Answer the question, please? Has Intel ever come out with a non-crippled DDR chipset for the P4? How do Intel's DDR P4 chipsets compare to non-intel DDR P4 chipsets? (ARE there any non-intel P4 chipsets?)

    How much of the problem is political, and how much of it is a real technical issue?

  8. Re:Tom, as usual, not 100% by sigwinch · · Score: 4, Insightful
    For example, signal integrity issues. I can say with complete assurance that Rambus is loaded with signal integrity issues. These issues get -very bad- as the clock frequency goes up.
    Bad as in you have to be aware of dielectric losses in the PCB material. I remember seeing reflectometer graph of a Rambus system where the plateaus were noticeably sloping from dielectric loss.
    Also Rambus is -not-, strictly speaking, a serial bus.
    Serial != 1 bit. Serial == takes more than one clock cycle to transfer a word.
    --

    --
    Kuro5hin.org: where the good times never end. ;-)

  9. Re:I refuse to believe tomshardware.com anymore by Chris+Burke · · Score: 5, Insightful

    Um... How was that FUD?

    It's true. If the heatsink falls off your Athlon it is toast. (note that just in the last week or so a board was released that supported the XP's thermal diode... but for all other boards/chips, you still get toast)

    Tom isn't the genius a lot of people think he is (or that he'd want you to think), but that was not FUD.

    --

    The enemies of Democracy are
  10. Quantity vs Quality by daviddennis · · Score: 3, Insightful

    First, it looks to me like RDRAM is still about double the cost of SDRAM, according to Tom's Hardware's own price guide.

    They have $93 for 512mb SDRAM and $175-250 for 512mb RDRAM.

    My question is this: Let's say I have a choice between 512mb of SDRAM and 256mb of RDRAM. Would the SDRAM not almost always be faster because RAM, however slow, trumps swap space every time?

    In other words, isn't the amount of memory I have more important than how fast it is?

    Many moons ago, I had a SGI O2 workstation. Tremendous memory bandwidth, but memory that cost 10x more than anything else. As a result, it could be embarassed by lesser machines, since I couldn't afford to load it up with RAM.

    I see Intel repeating the same mistake when it decided to focus on RDRAM.

    Apple is putting L3 cache in their G4s so that the use of expensive RAM is confined to a relatively small and affordable amount. I can upgrade my PC133-equipped G4/450 dual processor to the latest 1ghz dual processor, put my 1.5gb RAM in it, and fly. That seems like a good compromise to me, maybe better than going to DDR, which I would have to buy new.

    Thoughts?

    D

    1. Re:Quantity vs Quality by Jemima+Fei · · Score: 2, Insightful

      First, it looks to me like RDRAM is still about double the cost of SDRAM, according to Tom's Hardware's own price guide.
      They have $93 for 512mb SDRAM and $175-250 for 512mb RDRAM.



      Tom's price guide is not usually the place to find the lowest prices on hardware. But it's also not entirely fair to compare RDRAM prices with normal SDRAM prices, because of the performance difference and shrinking platform availability for non-DDR SDRAM.
      If you look at pricewatch.com, though we can find some prices like these:
      Samsung 512MB RIMM for $156 + $9 shipping from some provider called 11cb. I simply picked this as the cheapest Samsung-labeled provider, since Samsung provides some of the best RDRAM. Keep in mind for interleaved operation that you'll actually be using two RIMMs, so you might instead want to compare 2x256MB or simply look at 2x512MB for your other RAM platforms.

      From SDRAM and DDR SDRAM I'll just pick Crucial/Micron, while they won't be picked as the high-performance provider (people would be more apt to pick Mushkin or Corsair for performance) you'll see much less flakiness than with a non-labeled generic provider.

      (Shipping not mentioned with Crucial, check their site)

      Micron 512MB PC133 CL2.5 $139 + $10 shipping from "Alpha International Business Inc."

      Crucial 512MB PC133 CL3 $139 Crucial 512MB PC2100 CL2.5 $152

      Now for the faster DDR I'll pick the lowest reputable name-brand item, since Micron/Crucial don't offer all speeds of DDR, currently.

      Corsair 512MB PC2400 CL2 $187 + $9.74 shipping from Googlegear.com

      Mushkin 512MB PC2700 CL2.5 $211 + $9 shipping from Mushkin


      Now, I don't intend for you to read too much into this, but provided you stay with "non-crap" providers of memory, the closer you come to the performance levels of RDRAM, the less you see a price difference in favor of SDRAM.


      My question is this: Let's say I have a choice between 512mb of SDRAM and 256mb of RDRAM. Would the SDRAM not almost always be faster because RAM, however slow, trumps swap space every time?

      In other words, isn't the amount of memory I have more important than how fast it is?



      If you aren't being limited by the amount of system memory, then no. Provided that for your application at hand you don't need more memory than you currently have available, swap access differences really aren't an issue. Does it matter that you have 1GB of memory if you only use a small portion of it for something other than disk cache, when compared to 512MB of memory with much more bandwidth?
      If you don't need or can't use the bandwidth, then of course it's not overly useful. Or if you need to access more data than you can realistically ever store in memory, then there will be a point where memory bandwidth is made mood by increased disk access. It's a matter of application and necessity of your processor.

      The Pentium 4 sees very realistic gains from using RDRAM versus DDR memory, because of how it was designed.
      At one point Intel was being embarrassed by the absurd cost of RDRAM, but times have changed. It's continued to go down in price, and DDR and normal SDRAM have recently increased in price.

  11. Re:I refuse to believe tomshardware.com anymore by Jemima+Fei · · Score: 2, Insightful

    Though some might argue that the role of the preview option is to avoid such errors, I am inclined to agree with you. Either due to a lack of willingness to bother to preview, or simply because mistake initially escape your view, an "Edit" option would be most helpful. I'm almost entirely certain that many would argue that it would be abused (for instance, posting something insightful and receiving a bonus, and then swapping to an ASCII penis). Of course there are numerous safeguards that could be utilized to reduce the likelihood of this.

  12. Re:Why does everyone hate rambus? by Jemima+Fei · · Score: 3, Insightful

    Historically RDRAM has been plagued by cost, which has deterred its adoption, but this isn't why average reader of Slashdot dislikes it. They might claim that they think it's technically inferior (PC600 and PC800 have more latency than SDRAM, but PC1066 and PC1200 RDRAM will likely be out within the next year), I think a large majority of hatred of RDRAM comes from Intel and Rambus's business practicates.
    Intel and Rambus were hoping to strangle the market into adopting RDRAM in order to hurt Intel's competitors, and when this failed (RDRAM's prices lead people to adopt PC133 and then DDR), they attempted to obtain royalties or sue developers of alternative memory technologies for patent infringement of one form or another.