Power Consumption: Who is the king?

Intel promised us better performance per watt, lower energy consumed per instruction, and an overall serious reduction in power consumption with Conroe and its Core 2 line of processors. Compared to its NetBurst predecessors, the Core 2 lineup consumes significantly lower power - but what about compared to AMD?

This is one area that AMD is not standing still in, and just days before Intel's launch AMD managed to get us a couple of its long awaited Energy Efficient Athlon 64 X2 processors that are manufactured to target much lower TDPs than its other X2 processors. AMD sent us its Athlon 64 X2 4600+ Energy Efficient processor which carries a 65W TDP compared to 89W for the regular 4600+. The more interesting CPU is its Athlon 64 X2 3800+ Energy Efficient Small Form Factor CPU, which features an extremely low 35W rating. We've also included the 89W Athlon 64 X2s in this comparison, as well as the 125W Athlon 64 FX-62.

Cool 'n Quiet and EIST were enabled for AMD and Intel platforms respectively; power consumption was measured at the wall outlet. We used an ASUS M2NPV-VM for our AM2 platform and ASUS' P5W DH Deluxe for our Core 2 platform, but remember that power consumption will be higher with a SLI chipset on either platform. We used a single GeForce 7900 GTX, but since our power consumption tests were all done at the Windows desktop 3D performance/power consumption never came into play.

We took two power measurements: peak at idle and peak under load while performing our Windows Media Encoder 9 test.

System Level Power Consumption at Idle

Taking into consideration the fact that we were unable to compare two more similar chipsets (we will take a look back at that once retail Intel nForce 5 products hit the shelves), these power numbers heavily favor Intel. The releative power savings over the Extreme Edition 965 show just how big the jump is, and the ~15% idle power advantage our lower power AMD motherboard has over the Intel solution isn't a huge issue, especially when considering the performance advantage for the realtively small power investment.

System Level Power Consumption under Full Load

When looking at load power, we can very clearly see that AMD is no longer the performance per watt king. While the Energy Efficient (EE) line of X2 processors is clearly very good at dropping load power (especially in the case of the 3800+), not even these chips can compete with the efficiency of the Core 2 line while encoding with WME9. The bottom line is that Intel just gets it done faster while pulling fewer watts (e.g. Performance/Watt on the X6800 is 0.3575 vs. 0.2757 on the X2 3800+ EE SFF).

In fact, in a complete turn around from what we've seen in the past, the highest end Core 2 processor is actually the most efficient (performance per Watt) processor in the lineup for WME9. This time, those who take the plunge on a high priced processor will not be stuck with brute force and a huge electric bill.

FSB Bottlenecks: Is 1333MHz Necessary? Application Performance using SYSMark 2004 SE
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  • crystal clear - Saturday, July 15, 2006 - link

    Just to remind all that-" Intel decides to release a B2 stepping of its Conroe
    processors.Also
    BEWARE of Engineering samples & reviews based on Engineering samples inlcuded.
    Reply
  • OcHungry - Saturday, July 15, 2006 - link

    I don’t know if this Q been asked or answered (sorry no time reading 120 posts)
    Bu Mr. Anand, can I kindly ask you couple of concerns:
    1) why don’t we see any reference to temp. under load? Temp. is a crucial factor in deciding wether or not I buy conroe since I live in a very hot climate.
    2)A lot people make reference to 64bit and window vista and that conroe is a 32bit architecture and will not perform as good in 64bit. Is it true? can we have some 64bit benchmarks? It would be great to do this test in multitasking.
    3) I have also noticed (from so many who have had pre-release ES @ XS, and other forums) that overclocked conroe does not correspond directly to performance, unlike A64.
    What I mean is: If A64 is overclocked 20%, the performance increases ~20% 9more or less, in most cases), But have not seen this to hold w/ conroe. So I am wondering what would happen if we put a low end conroe, such as E6400 against A64 4000 x2, 2x1mb cache (same price range after price drop) and overclock them to their limit, using stock cooling, and do the benchmarks (64bit included). The reason I am interested in this type of review is because I am an average end user on budget and would like to know which would give me better price/performance. I think I am speaking for at least 90% of consumers. Not everyone buys $1000 cpu and consumers on budget is detrimental to survival of conroe or AM2 cpus. This alone should give you enough incentive to put together a review oriented around us, the mainstream computer users. We can make or break any chipmaker.
    So please Mr. Anad, can we have another review along those lines described above?
    We greatly appreciate it.
    Thanks,
    ochungry
    Reply
  • aznskickass - Saturday, July 15, 2006 - link

    Hey ochungry, I believe Xbitlabs did an overclocking comparison between a Conroe E6300 and an A64 X2 3800+, and while they didn't do any 64bit benchmarks, the conclusion is that at stock speeds the E6300 is slightly faster than X2 3800+, and when both are overclocked to the max, E6300's lead increases even more.

    Here is the review/comparison:
    http://xbitlabs.com/articles/cpu/display/core2duo-...">http://xbitlabs.com/articles/cpu/display/core2duo-...
    Reply
  • OcHungry - Saturday, July 15, 2006 - link

    Those guys @ X-bit lab do not fool me. And I hope Anandtech conducts the same test w/ best suited memory module for “BOTH” platforms. We know (so as Xbitlab knows) that, because of IMC, A64 performs its best @ tightest memory timings. X-bit lab should have used http://www.newegg.com/Product/Product.asp?Item=N82...">This memory module if the test was going to be fair and square. Furthermore A64 3800 x2 @ 3ghz is 10x300, which means DDR2 667 1:1 could have been better to use. This http://www.newegg.com/Product/Product.asp?Item=N82...">DDR2 667 @ 3-3-3-10 would have given about 10% better performance than DDR2 4-4-4-12 that they used. X-bit does not mention anything about memory/cpu ratio. What divider was used? Was it 133/266? Or as close to 1:1 as possible? Sooner or later the truth will prevail when we end users try it for ourselves (oh BTW, not ES), and we will see if xbitlab and others were genuinely interested on behalf of consumers, or the interest destined to ill-fated purpose. Will not accuse anyone, but it all look very fishy.
    I am certain that Mr. Anad will clear all these conspicuous reviews , and hand us another that concerns the consumer’s majority- us average users.
    Reply
  • IntelUser2000 - Saturday, July 15, 2006 - link

    quote:

    We know (so as Xbitlab knows) that, because of IMC, A64 performs its best @ tightest memory timings. X-bit lab should have used This memory module if the test was going to be fair and square. Furthermore A64 3800 x2 @ 3ghz is 10x300, which means DDR2 667 1:1 could have been better to use. This DDR2 667 @ 3-3-3-10 would have given about 10% better performance than DDR2 4-4-4-12 that they used.


    W-R-O-N-G!!! DDR2-800 at EVEN slower 5-5-5-15 timings is FASTER THAN DDR2-667 3-3-3-10: http://xbitlabs.com/articles/cpu/display/amd-socke...">http://xbitlabs.com/articles/cpu/display/amd-socke...

    Prefer AT's results?: http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">http://www.anandtech.com/cpuchipsets/showdoc.aspx?...

    DDR2-800 is faster. The myth that it performs amazingly better(comparatively) with lower latency is just, a myth. I believe there was a thread in forums that tells exactly that.
    Reply
  • OcHungry - Sunday, July 16, 2006 - link

    Iguess you don’t understand much about AMD's memory latency, direct connect, and 1:1 ratio.
    It is not like Intel's illusionary, that faster than FSB is better. It is not and is useless. Anad proved it here. But this subject has a tendency to be dragged on for ever by those who don’t understand the concept of IMC. So it's better leave it alone.
    But I still would like to see tightest timing and 1:1 ratio. It is now clear to me that those reviews in favor of Intel, artfully evade this argument/request, knowing it will give AMD advantage over Intel's FSB.
    Reply
  • aznskickass - Sunday, July 16, 2006 - link

    *sigh*

    How is the AMD disadvantaged if BOTH platforms are reviewed using the same RAM?

    AMD needs ultra low latency DDR2 to attain best performance? Well, bad luck, Intel doesn't , there is no 'deliberate' conspiracy to put AMD in a bad light.

    Look, if you just want to hang on to the notion that AMD has been cheated in the reviews, then go ahead and get your X2 4200+ and see how close you can get to Conroes numbers.

    I'll be using my E6600 @ 3.5GHz+ and laughing at your stupidity.
    Reply
  • aznskickass - Saturday, July 15, 2006 - link

    I consider Xbitlabs to be one of the more trustworthy sites around, and do note that they are testing mainstream chips, and expensive CL3 DDR2 just doesn't make sense in a budget setup, which further puts Conroe in a good light, as it doesn't require expensive CL3 DDR2 to perform well. Reply
  • sum1 - Friday, July 14, 2006 - link

    A good read. For the editor, I found 4 errors, search the full lines of text below at:
    http://www.anandtech.com/printarticle.html?i=2795">http://www.anandtech.com/printarticle.html?i=2795

    That begin said,
    and H.264 in coding
    as soon as its available
    at the fastest desktop processor we've ever tested
    ("and" would be more readable that "at" in this sentence)
    Reply
  • JarredWalton - Friday, July 14, 2006 - link

    Thanks. At least one of those (in coding) can be blamed on my use of Dragon NaturallySpeaking and not catching the error. The others... well, they can be blamed on me not catching them too. LOL. The last one is sort of a difference of opinion, and I've replaced the comma with a dash, as that was the intended reading. :)

    --Jarred
    Reply

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