AMD's Quad FX: Technically Quad Core
by Anand Lal Shimpi on November 30, 2006 1:16 PM EST- Posted in
- CPUs
Four cores, 1 Socket or Four cores, 2 Sockets?
One of the major arguments in favor of AMD's Quad FX architecture is the fact that you should get better performance scaling when going from 2 to 4 cores since there's no FSB limiting the data coming in to the CPUs. We looked at the performance scaling from a single FX-74 to two FX-74 processors in our Quad FX platform and compared it to Intel's Core 2 running at 2.66GHz with two and four cores enabled.
| Benchmark | AMD Scaling (2 to 4 cores) | Intel Scaling (2 to 4 cores) |
| 3dsmax 8 | 64.7% | 77.0% |
| Cinebench | 75.6% | 70.8% |
| DivX 6.4 | 29.5% | 35.0% |
| WME9 | 53.2% | 54.8% |
| Blu-ray + Cinebench | 147% | 135% |
| Blu-ray + DivX | 43.9% | 48.3% |
| Blu-ray + WME | 65.4% | 73.4% |
| Blu-ray + 3dsmax 8 | 63.1% | 77.0% |
| Valve Particle Systems | 48.8% | 93.1% |
| Valve Map Compilation | 42.0% | 44.3% |
Even when we take into account our heavy multitasking Blu-ray playback scenarios (which we will describe later), AMD's Quad FX doesn't scale any better than Intel's quad-core solution. All things being equal, AMD should have better scaling, however AMD's cores are inherently slower in most of these benchmarks and thus simply adding more of them is not going to make up for the deficit seen by one.
AMD will have better scaling on paper, but Intel has the superior micro-architecture today, which results in better performance and in most cases, better scaling than AMD. The same might not be true in the enterprise market, but we'll have to save that for a look at Opteron vs. Xeon.
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BikeDude - Tuesday, December 5, 2006 - link
Could the reason be that 1GB per memory node is simply too little?On a configuration like this, you'll easily see one of the nodes with only 256MB or so left...
So, put in some more memory! At this point 32-bit XP will be limiting, even for 32-bit apps. (XP won't address more than 2^32 Bytes, some of this will be masked by PCI and PCIe devices, and additionally each process only has a 2GB address space for code&data unless you upgrade to 64-bit Windows) Also be aware that nVidia ForceWare 80.00 and newer lost PAE support. You'll experience crashes and non-working games if combined with a PAE aware 32-bit OS (such as Win2003). ForceWare 79.11 works fine though.
(BTW: MSFT added NUMA support in XP SP2)
Kiijibari - Saturday, December 2, 2006 - link
Hi Ananand,sounds credible, because there is some extra cache snooping traffic going on, anyways, please keep us posted if there is a new BIOS version available, and if it would "do" something :)
Windows schweduler differences between XP and VISTA would be interesting, too.
So far there were only Win32 XP vs. Win Vista64 comparisions, not possible to draw a fair conclusion with that data.
Thanks a lot
Kiijibari
mino - Friday, December 1, 2006 - link
One important question:Are those new FX-7x CPU identical or is there some differentiation employed ???
Kiijibari - Saturday, December 2, 2006 - link
identical to what ?If you meant Socket-F Opterons, then yes, they are identical, if the BIOS allows it, then normal Opterons should be able to run in 4x4 boards, too.
cheers
Kiijibari
mino - Sunday, December 3, 2006 - link
Thanks that info(if correct) pretty much clears the FUD.Griswold - Saturday, December 2, 2006 - link
How so? The 2P+ Opteron IMC wants buffered RAM, while these FX types do not. I dont think a simple BIOS hack can circumvent that.Kiijibari - Saturday, December 2, 2006 - link
*gasp*Du you really think AMD engineers, tests, validate, etc. a CPU for a niche market ??
There are maybe only a few thousand 4x4 CPUs, that are sold worldwide per month ... it would be economical ridiculous.
But if you dont know anything about business, maybe that will convince you:
http://www.aceshardware.com/forums/read_post.jsp?i...">http://www.aceshardware.com/forums/read_post.jsp?i...
cheers
Kiijibari
lollichop - Sunday, February 26, 2017 - link
All idiots talking about old CPUs here :D Fast forward 11 years, Ryzen will be out in a week's time.