Energy Consumption

We tested the energy consumption of our servers for a one-minute period in several scenario. The first scenario is the point where the server under testing performs best in MySQL: the highest throughput just before the response time goes up significantly. 

To test the power usage of the FPU, we measure the power consumption when POV-Ray was using all available threads. 

SKU TDP
(on paper)
spec
Idle
Server

W
MySQL
Best Throughput
at Lowest Resp. Time (*)
(W)
POV-Ray
100% CPU load
Dual Xeon E5-2699 v4 2x145 W 106 412 425
Dual Xeon 8176  2x165W 190 300 453
Dual EPYC 7601 2x180W 151 321 327

Both the Xeon 8176 and Dual EPYC server had a few more additional components (a separate 10 GBe card for example) than the Dual Xeon E5-2699v4 system, but that does not fully explain why idle power is so much higher, especially on the Dual Xeon 8176. We lacked the time to fully investigate this, and the last two systems have relatively new firmware.

The only conclusion that we can draw so far, is that the EPYC 7601 is likely to draw more power when running integer applications, while the rather wide FP units of the Intel CPUs are real power hogs even if they do not run heavy AVX applications. To be continued...

Floating Point performance Closing Thoughts
Comments Locked

219 Comments

View All Comments

  • PixyMisa - Tuesday, July 11, 2017 - link

    No, the pricing is correct. The 1P CPUs really are half the price of a single 2P CPU.
  • msroadkill612 - Wednesday, July 12, 2017 - link

    Seems to me, the simplest explanation of something complex, is to list what it will not do, which they will not do :(.

    Can i run a 1p Epyc in a 2p mobo e.g., please?
  • PixyMisa - Thursday, July 13, 2017 - link

    Short answer is no. It might boot, but only half the slots, memory, SATA and so on will be available. Two 1P CPUs won't talk to each other.

    A 2P Epyc will work in a 1P board though.
  • cekim - Tuesday, July 11, 2017 - link

    One glaring bug/feature of AMD's segmentation relative to Intel's is the utter and obvious crippling of clock speeds for all but the absolute top SKUs. Fewer cores should be able to make use of higher clocks within the same TDP envelope. As a result Intel is objectively offering more and better fits up and down the sweep of cores vs clocks vs price spectrum.

    So, the bottom line is AMD is saying that you will have to buy the top-end, 4S SKU to get the top GHz for those applications in your mix that won't benefit from 16,18,32,128 cores.

    I say all of this as someone who desperately wants EPYC to shake things up and force Intel to remove the sand-bags. I know I'm in a small, but non-zero market of users who can make use of dozens of cores, but still need 8 or fewer cores to perform on par with desktop parts for that purpose.
  • KAlmquist - Wednesday, July 12, 2017 - link

    One possibility is that they have only a small percentage of the chips currently being produced bin well enough to be used in the highest clocking SKU's, so they are saving those chips for the most expensive offerings. Admittedly, that depends on what they are seeing coming off the production line. If they have a fair number of chips where with two very good cores, and two not so good, then it would make sense to offer a high clocking 16 core EPYC using chips with two cores disabled. But if clock speed on most chips is limited due to minor registration errors (which would affect the entire chip), then a chip with only two really good cores would require two localized defects in two separate cores, in addition to very good registration to get the two good cores. The combination might be too rare to justify a separate SKU.

    I would expect Global Foundries to continue to tweak its process to get better yields. In that case, more processors would end up in the highest bin, and AMD might decide to launch a higher clock speed 16 and 8 core EPYC processors, mostly using chips which bin well enough that they could have been used for the 32 core EPYC 7601.
  • alpha754293 - Tuesday, July 11, 2017 - link

    Why does the Intel Xeon 6142 cost LESS than the 6142M? (e.g. per the table above, 6142 is shown with a price of $5946 while the 6142M costs $2949)
  • ca197 - Tuesday, July 11, 2017 - link

    I assume that is the wrong way round on the list. I have seen it reported the other way round on other sites.
  • Ian Cutress - Tuesday, July 11, 2017 - link

    You're correct. I've updated the piece, was a misread error from Intel's tables.
  • coder543 - Tuesday, July 11, 2017 - link

    On page 6, it says that Epyc only has 64 PCIe lanes (available), but that's not correct. There are 128 PCIe lanes per chip. In a 1P configuration, that's 128 PCIe lanes available. On a 2P configuration, 64 PCIe lanes from each chip are used to connect to the other chip, leaving 64 + 64 = 128 PCIe lanes still available.

    This is a significant advantage.
  • Ian Cutress - Tuesday, July 11, 2017 - link

    You misread that table. It's quoting per-CPU when in a 2P configuration.

Log in

Don't have an account? Sign up now