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Xeons, Opterons Compared in Power Efficiency

Posted by Zonk on from the nothing-like-some-friday-morning-power-analysis dept.

Bender writes "The Tech Report has put Intel's 'Woodcrest' and quad-core 'Clovertown' Xeons up against AMD's Socket F Opterons in a range of applications, including widely multithreaded tests from academic fields like computational fluid dynamics and proteomics. They've also attempted to quantify power efficiency in terms of energy use over over time and energy use per task, with some surprising results." From the article: "On the power efficiency front, we found both Xeons and Opterons to be very good in specific ways. The Opteron 2218 is excellent overall in power efficiency, and I can see why AMD issued its challenge. Yes, we were testing the top speed grade of the Xeon 5100 and 5300 series against the Opteron 2218, but the Opteron ended up drawing much less power at idle than the Xeons ... We've learned that multithreaded execution is another recipe for power-efficient performance, and on that front, the Xeons excel. The eight-core Xeon 5355 system managed to render our multithreaded POV-Ray test scene using the least total energy, even though its peak power consumption was rather high, because it finished the job in about half the time that the four-way systems did. Similarly, the Xeon 5160 used the least energy in completing our multithreaded MyriMatch search, in part because it completed the task so quickly. "

5 of 98 comments (clear)

  1. Re:God, I'm sick of this architecture by Ancil · · Score: 5, Informative
    bizzaro CISC instruction set piece of shite
    I guess you didn't get the memo. Turns out RISC wasn't the good idea everyone thought it would be in the 1990's.

    RISC worked well when speed of memory and CPU's were at parity. The simplified instructions let the CPU be clocked a lot faster, not to mention their shallow pipelines made it less costly when branch prediction failed. The tradeoff was that it usually took more instructions to accomplish a given task.

    But as CPU's have spent more and more time waiting for memory, CISC has really come into its own. Think of CISC as a compression algrorithm: An x86 instruction which fits in 16-32 bits might take 4 or 5 instructions on a RISC processor, weighing in at 96-128 bits. It's no surprise why CISC processors have destroyed RISC in the past decade.
  2. oracle datacenter by chap_hyd · · Score: 4, Informative

    one friend who works for oracle, in their datacenter, told me that they are swaping the dell intel xeon server with Sun AMD Opteron servers. the main reason behind this server swap is power efficiency of the new sun servers. So that means big corps already had their eye on AMD cpus :)

    1. Re:oracle datacenter by aczisny · · Score: 2, Informative
      A basic server, costing about $4k (nothing fancy), running 24x7x365.25 at about 300Watts, will use 18408.6 KWH in one year. At $0.07/KWH, thats $1288.60 per year just to power the box.

      It took me forever to figure out what was wrong with this. I knew your numbers didn't add up but I couldn't put my finger on it until I realized you multiplied out exactly what people say when they mean constant uptime. The problem of course, is that it should be 300(watts)*24(hours/day)x365(days/year) or 24(hours/day)x7(days/week)x52(weeks/year) to get the power used in a year. You end up with 2628 KWH a year. At $0.07/KWH you get $183.96 which is much more reasonable. Not something I'd ignore as a business with hundreds of machines, but not a quart of the cost of the machine itself either.

      As my chemistry teacher always used to tell me, UNITS! It's all about keeping proper track of your units!

      --
      Now, landing thrusters.. landing thrusters, hmm. Now if I were a landing thruster, which one of these would I be?
  3. HOWTO: save 20W/socket when idle on Opteron or A64 by Splork · · Score: 4, Informative

    See http://electricrain.com/greg/opteron-powersave.txt .

    All AMD K8 (Opteron and Athlon 64) CPUs have the ability to run the clock and an extra slow speed when in HLT (idle) mode saving a bunch more power. Many (most?) BIOSes are not smart enough to enable this. A simple setpci command will turn it on under linux.

    find out if its on:

      setpci -d 1022:1103 87.b

    If that returns 00, its off. To turn on clock-divide-in-hlt to div by 512 mode use:

      setpci -d 1022:1103 87.b=61

    (see the above URL for links to the AMD documentation on the PMM7 register; other values can work).

  4. Re:What About Efficiency as a Space Heater by frieko · · Score: 2, Informative

    That light you mention ends up as heat too.