AMD's Quad FX: Technically Quad Core
by Anand Lal Shimpi on November 30, 2006 1:16 PM EST- Posted in
- CPUs
Power Consumption
Power consumption of a Quad FX system is simply unreal for a desktop, as it should be because this is effectively a workstation platform with un-buffered memory. At idle our Quad FX test bed consumed nearly 400W, partially because we couldn't get Cool 'n Quiet running on the system, but also because the CPUs and motherboard simply draw an incredible amount of power. Update: We got Cool 'n Quiet working on the motherboard which reduced idle power significantly, down to within a few watts of the Kentsfield system. Load power was unchanged.
| CPU | Idle Power | Load Power | Performance per Watt (fps/watt) |
| AMD Athlon 64 FX-74 (3.0GHz x 4) | 217W | 456W | 17.7 |
| Intel Core 2 Extreme QX6700 (2.66GHz x 4) | 213W | 263W | 32.9 |
Looking at power consumption under full load, Cool 'n Quiet would have no chance to even make an impact as all cores are being utilized at full speed. Under load the Quad FX system pulled 456W on average, a full 73% more than our Kentsfield testbed.
If we look at performance per watt, the Quad FX loses big time. We specifically chose to look at our WME encoding test because the performance of the FX-74 and QX6700 is pretty close. What you're looking at here is the best case scenario for the Quad FX's performance per watt; in applications where it's significantly slower than Kentsfield the performance per watt will be even worse.
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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.