Power Consumption

The most power hungry 2.93GHz Nehalems are sold in the desktop market (130W TDP), while the "greenest" ones are sold in the server market (95W). It is clear that Intel understands that performance alone is not good enough and the performance/watt metric is getting more popular each day. A direct power comparison was not possible, as the servers are too different: different power supplies, form factors, and so on. Therefore, we tested in a different way. First, we tested the server with two CPUs. Second, we tested the server with one CPU, while we kept the number of DIMMs the same. That way we could subtract both numbers and calculate the difference that one CPU made. It is not very accurate, but it's good enough to get a rough idea. The CPUs were running at about 80% CPU load, running the DVD-store benchmark for 10 minutes. Below you find the average power consumption.
 
Power Consumption

The method we used does not allow us to determine the absolute idle power numbers very accurately, but it seems that Xeon X5570 consumes 8W to 10W less when running at idle. Again, all these numbers have a pretty high margin of error, but they are accurate enough to say that the Opteron 2384 consumes quite a bit less at full load while the latest Xeon is clearly the winner when you are running idle. If your application is running close to idle most of the time, with a few spikes at some parts of the day, the Xeon is the performance/watt champion.

The only question is what happens if the server is running most of the time at relatively high load (for example thanks to virtualization)? Then we have to remember that the CPU is only part of a complete server. Let us assume that the Nehalem server consumes 320W (which is close to what we measured). A similar AMD Opteron server can then save about 18W per CPU, and 1W per DIMM as high speed DDR3 is a bit more power hungry than DDR2 (which runs at a lower speed). We assume that we use six DIMMs per CPU.

Power Comparison
  Power consumption Performance Performance/Watt
Intel X5570 2.93GHz 320 116399 363.7469
AMD 270 70034 259.3852

We could say that the Nehalem is winning by a margin of about 40%. Now, it is clear that the absolute winner is difficult to determine; it all depends on your applications. Still, it is clear that when you compare the best Intel and AMD CPUs, the best performance/Watt figures come from Intel by pretty large margin.

HPC Market Pricing
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  • gwolfman - Tuesday, March 31, 2009 - link

    Why was this article pulled yesterday after it first posted?
  • JohanAnandtech - Tuesday, March 31, 2009 - link

    Because the NDA date was noon in the pacific zone and not CET. We were slightly too early...
  • yasbane - Tuesday, March 31, 2009 - link

    Hi Johan,

    Any chance of some more comprehensive Linux benchmarks? Haven't seen any on IT Anandtech for a while.

    cheers
  • JohanAnandtech - Tuesday, March 31, 2009 - link

    Yes, we are working on that. Our first Oracle testing is finished on the AMD's platform, but still working on the rest.

    Mind you, all our articles so far have included Linux benchmarking. All mysql testing for example, Stream, Specjbb and Linpack.
  • Exar3342 - Monday, March 30, 2009 - link

    Thanks for the extremely informative and interesting review Johan. I am definitely looking forward to more server reviews; are the 4-way CPUs out later this year? That will be interesting as well.
  • Exar3342 - Monday, March 30, 2009 - link

    Forgot to mention that I was suprised HT has such an impact that it did in some of the benches. It made some huge differences in certain applications, and slightly hindered it in others. Overall, I can see why Intel wanted to bring back SMT for the Nehalem architecture.
  • duploxxx - Monday, March 30, 2009 - link

    awesome performance, but would like to see how the intel 5510-20-30 fare against the amd 2378-80-82 after all that is the same price range.

    It was the same with woodcrest and conroe launch, everybody saw huge performance lead but then only bought the very slow versions.... then the question is what is still the best value performance/price/power.

    Istanbul better come faster for amd, how it looks now with decent 45nm power consumption it will be able to bring some battle to high-end 55xx versions.
  • eryco - Tuesday, April 14, 2009 - link

    Very informative article... I would also be interested in seeing how any of the midrange 5520/30 Xeons compare to the 2382/84 Opterons. Especially now that some vendors are giving discounts on the AMD-based servers, the premium for a server with X5550/60/70s is even bigger. It would be interesting to see how the performance scales for the Nehalem Xeons, and how it compares to Shanghai Opterons in the same price range. We're looking to acquire some new servers and we can afford 2P systems with 2384s, but on the Intel side we can only go as far as E5530s. Unfortunately there's no performance data for Xeons in the midrange anywhere online so we can make a comparison.
  • haplo602 - Monday, March 30, 2009 - link

    I only skimmed the graphs, but how about some consistency ? some of the graphs feature only dual core opterons, some have a mix of dual and quad core ... pricing chart also features only dual core opterons ...

    looking just at the graphs, I cannot make any conclusion ...
  • TA152H - Monday, March 30, 2009 - link

    Part of the problem with the 54xx CPUs is not the CPUs themselves, but the FB-DIMMS. Part of the big improvement for the Nehalem in the server world is because Intel sodomized their 54xx platform, for reasons that escape most people, with the FB-DIMMs. But, it's really not mentioned except with regards to power. If the IMC (which is not an AMD innovation by the way, it's been done many times before they did it, even on the x86 by NexGen, a company they later bought) is so important, then surely the FB-DIMMs are. They both are related to the same issue - memory latency.

    It's not really important though, since that's what you'd get if you bought the Intel 54xx; it's more of an academic complaint. But, I'd like to see the Nehalem tested with dual channel memory, which is a real issue. The reason being, it has lower latency while only using two channels, and for some benchmarks, certainly not all or even the majority, you might see better performance by using two (or maybe it never happens). If you're running a specific application that runs better using dual channel, it would be good to know.

    Overall, though, a very good article. The first thing I mention is a nitpick, the second may not even matter if three channel performance is always better.

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