Power

AMD has made numerous improvements compared to the K8 core:
  • The FPU unit can be turned off when not needed
  • Clock gating is implemented much better
  • Each core can run at its own frequency (but the voltage is the highest needed by either core)
  • Power for the core and memory controller are split

We measured power consumption using two identically configured Colfax systems running Windows 2003 SP1 64-bit. The server configuration is listed below:

AMD Intel
Motherboard Supermicro H8DMU+ Supermicro X7DBE+
BIOS Revision DMU8157v3.ROM R1.3C
CPU 2 x Opteron 2350 (2.0GHz) 2 x Xeon 5345 (2.3GHz)
Memory 8GB (8 x 1GB DDR2-667) 8GB (8 x 1GB FBDIMM-667)
Hard Disk 1 x Seagate Barracuda ES (400GB) 1 x Seagate Barracuda ES (400GB)
Power Supply 700W Redundant 700W Redundant
OS Windows Server 2003 SP1, 64-bit Windows Server 2003 SP1, 64-bit

At idle, the Opteron 2350 platform uses significantly less power than the Xeon setup, a decrease of about 44%. While Intel will be able to drop its power consumption with the move to 45nm, the impact won't be great enough to close this gap. The problem here is that Intel must use FB-DIMMs which consume significantly more power than AMD's registered DDR2, short of switching memory technologies there's nothing Intel can do.

CPU Idle Load (Cinebench R10 XCPU) Performance per Watt (Cinebench Score/Watts)
Dual Opteron 2350 188W 299.9W 41.9
Dual Xeon 5345 257W 347.3W 47.4

Under load, the two are closer in power consumption with the Xeon only using 16% more total system power. Looking at performance per watt, Intel is actually ahead thanks to superior performance under the Cinebench R10 benchmark.

Fritz Chess Conclusion
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  • JohanAnandtech - Monday, September 10, 2007 - link

    well said. I don't think AMD will have that advantage for a long time in 2P space :-)
  • JackPack - Monday, September 10, 2007 - link

    The problem is, 45nm Harpertown and 1600 MHz FSB will be rolling in soon.

    Barcelona would have looked great 6 or 9 months ago. But today, it's a little weak unless they can raise the frequency fast.
  • Viditor - Monday, September 10, 2007 - link

    quote:

    45nm Harpertown and 1600 MHz FSB will be rolling in soon


    True, but so will HT 3.0 and the newer mem controller for the Barcelonas...
  • jones377 - Monday, September 10, 2007 - link

    You got your work cut out for you now :)
  • IntelUser2000 - Monday, September 10, 2007 - link

    AMD won't compete against Intel's Tulsa chips anymore. They will have to compete against Tigerton Xeon MP and the newly introduced Clarksbro chipset.

    On the DP server platform, Intel will introduce Harpertown and Seaburg chipset. Seaburg chipset features 1600MHz bus with significantly improved memory controller performance. We'll see how it all turns out but as of now, Barcelona is a bit late to be competitive.
  • wegra - Monday, September 10, 2007 - link

    You should not forget the Penryn. 2.5Ghz Barcelona will face to 3.1+Ghz Penryn. According to result from this article, I expect the performance of 2.5Ghz Barcelona will reach between 2.8 ~ 2.9Ghz Penryn. So wait till (hopefully) next year to see that AMD becomes the performance king. BTW, talking about the multi-processor servers, AMD will lead w/o much difficulties, I expect, thanks to the scalable architecture.

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