Slashdot Mirror
Are three cores better than two?
Barbarian writes "That's the question that Tom's Hardware asked. They took a dual-cpu motherboard and stuck both a single and a dual core Opteron on the board, for a total of three cores. Does it work? Well, yes, when it's not crashing. It does raise the possibility of tri-core processors whilst we are waiting for the next die shrink."
I thought the XBox CPU was a three-core jobby. I don't know if all the three cores are the same or whether thre are different sorts of cores for doing different sorts of things. Presumably, as long as you've got the correct glue, and can stick any number of cores on a chip. I don't think there's any need to stick (sorry!) to powers of two. Whether or not it works better efficiently becomes the issue... or rather the ability to market three vs two or four becomes the issue!
return 0; }
isnt even ready for multithreading yet.
Gaming is where the horsepower is needed in the consumer space - and most games aren't multithreaded. An additional core wont do much in terms of performance that a second core doesn't already accomplish. You're just wasting die space and decreasing yields.
The Doormat
If you're not outraged, then you're not paying attention.
Courtesy of Karma Whoring Copy-Paste technologies, Inc. (Patent Pending)
:P - no, this comment wasn't copy-pasted, doh. ]
---
Of course, we used our complete benchmark suite and we actually found some programs that were not working properly. Pinnacle Studio Plus 9.4.3 crashed repeatedly. Auto Gordian Knot, which we use for encoding DivX or XviD video, could not start the encoding process because it obviously was not able to access our AVI file. PCMark crashed sometimes right after finishing the compression test.
[ Flash Ad goes here
The problems are due to two processors types that are very different. Although both run at a 2.2 GHz clock speed, the single- core Opteron 248 is based on the 130 nm Sledgehammer design, while the dual-core Opteron 275 is a 90 nm Venice dual- core chip.
These two processors do not only differ in the manufacturing process: Changes to the memory controller have been made during the transition from 130 to 90 nm and SSE3 extensions were added. Opteron 248 was designed for HT800 (200 MHz bus), while the Opteron 275 is capable of running HT1000. Finally, the cache size per core is different as well.
Picking processors for dual-CPU machines sometimes was difficult in the past, because these often had to be at least the same product type, if not identical in order to run. All these facts we listed now basically made it unlikely that our asymmetric system would even be able to boot.
The fact that it worked served to prove that a triple-core system based on the same cores would only offer better results.
At the end of 1996, I was at an INTEL conference for their new "Intel processors integrators" salling mode.
;-).
They where showing the "hot" new stuff, Pentium MMX. And their demo was: 16 bit sound at 44.1 Khz !, can you believe it !?!. As if that was not possible before !. C'mon I was having that sound quality with my DX4-100, even with a "slow" 386-40 (AMD) that was possible, in DOS with MOD Players
I don't know what that people was smoking, but I didn't think that _that_ was impressive. Maybe with the overhead of winblows 95, that wasn't possible, true... but fancy graphics and flying papaers never seemed to me the way to go.
That sounds more like game programmers are wasting their time making games that don't make use of multiple CPUs. It's very clear that there are starting to be some limits reached in terms of what one CPU can do in a machine. There's a reason all these manufacturers are making dual core processors instead of making their processor faster. It's time for the programmers to change how they program.
So, I think your comment isn't very useful, since you try to tell hardware manufacturer's that they're doing useless things instead of making the single CPU faster. And that's not true at all. It's the game programmers that are doing stupid things. Going from 1 to 2 is would've been hard to deal with before it happened. But once you have, going from 2 to x is much easier. So, testing out three and more core systems is pretty useful.
Need a Python, C++, Unix, Linux develop
Apparently it's the mammoth power brick which causes most of the problems, coupled with people putting it in areas without good circulation (not necessarily the consumers fault... most entertainment centers are kinda cramped). Microsoft is saying that the defect rate is 3%, I'd believe something closer to 6%, but that is actually not out of the ordinary for consumer electronics.
So, in my mind, the "viability" issues of three cores has been answered with the 360. And in fact there are Power Mac configurations that effectively give you 4 cores (2x dual-cores). However, the bigger question is whether it will be advantageous .
With that in mind the 360 is a pretty good test-bed to see 3-core configs are worthwhile. Developers will have more incentive to exploit the potential with the assurance that the hardware will remain relatively constant (at least as far as the API is concerned... hopefully Microsoft will be able to come out with a more compact 360 in a few years).
I know replies have probably already covered this, but here it is one more time. The Xbox 360 uses 3 PowerPC cores (kind of funny for Microsoft to use PowerPC CPUs isn't it?). The new Xbox has major problems with heat, which can also be attributed to the power supply adding to the mess. A previous story said that at least one person was hanging his power supply by a string to help out, which is ridiculous.
We have hit a brick wall so to speak at which processors have been limited. There needs to be major changes in the way that the dies are manufactured before we can attain much higher speeds while keeping stability. One option is to stop using silicon to produce the circuitry, however thus far there are no economical solutions.
If you really need the extra processor power, network a couple of computers together and configure them to share their resources. This takes up more space, but is the only realistic answer that I can think of right now.
Actually this parent should be modded down. SMP doesn't refer to dual or single core, it jsut referes to multiple CPUs in general and it doesn't matter how many of them there are. It should run on two as well as on three or fifteen (depending on the implementation of course). What is crap though is when different CPUs are used, because software most likely wont expect this, as has been already explained in another posting regarding SSE or other special optimized code. It's not surprising either, because mmost software would determine special features at startup and not at runtime. Having a special instruction set would beg the question if the performance gain is negated by constant checks if this feature is still there.
I'm guessing there could be a lot done with AI that wouldn't require heavy communication between the different AI components. So, with careful design, most of the AI could fit in L1 cache andd be executed by one core without any bandwidth constraints.
Automota based models for physics engines might also be able to make good use of large numbers of parallel processors. I bet there are some interesting techniques for this in the scientific supercomuting sector that I don't know about yet.
Need a Python, C++, Unix, Linux develop
Have you ever spent time in mainframe environments? There are all kinds of "wacky" architectures to be found there.
My first job out of college was on a susyem with 3 CPU's. It was an MAI/B4 MPx8000 series mini. It had 9MB of RAM. Weirdly, the OS word size was 24 bits. Blocksize on the disk was 768 words.
I am very small, utmostly microscopic.
Saturday Night Live got there years before The Onion. They spoofed 2-blade razors with a 3-blade razor, and 2-color toothpaste with a 3-color toothpaste.
Based, presumably, on Saturday evening market research, Madison Avenue promptly brought to market a 3-blade razor and a 3-color toothpaste.
Sometimes they fool you by walking upright.
Please note that "TriCore" is a brand name (of Infineon, formerly Siemens Microelectronics).
It is an instruction set architecture (and a set of CPU cores that implement it). It is "Tri" core because it:
1) is a RISC architecture (for high crunch in low footprint) which
2) has instructions and data paths to do DSP work efficiently and
3) has the interrupt / task switching mechanisms to do real-time controller work efficiently, as well.
this gives ASIC designers a core that handles all three major sorts of embedded processing well in one package.
I suggest we stick to "triple core" (as most of the posters so far have) to avoid confusion between a chip with three cores and this branded single core that does three jobs well.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
These are basically the oddest benchmarks I've seen in a while, and nobody even seems to notice. Take for instance the "Cinema 4D R9" test; single Opteron, dual Opteron and dual-core Opteron are basically tied (the singe single-core is even a tiny bit faster!), but dual-core+single-core Opteron is a lot faster... Shouldn't such oddities (and that's not an isolated case) be at least commented on and explained in some sort of way if you want people to buy into your statistics at all? And why didn't they benchmark the rather obvious configuration of two dual-core CPUs?
/* Steinar */
(This comment is of course GPLed.)