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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  • finbarqs - Friday, July 14, 2006 - link

    just to show you how EASY it is to O/C the system! (and for the Futuremark junkies :-) )

    http://www.futuremark.com/forum/showthread.php?p=1...">http://www.futuremark.com/forum/showthread.php?p=1...

    You would want one :)

    if you want to know, 3DMark 2001SE posted a score of 45k, and 3DMark 2003 posted a 33k, FACTORY.
    Reply
  • phaxmohdem - Friday, July 14, 2006 - link

    I was wondering if you could possibly do some "single core" performance testing in the CPU's by simply changing the HAL to "ACPI Uniprocessor PC" instead of "multiprocessor PC" This would tel windows to only use one of the Core2 Duo cores, and I think would give us a good indication of how it will perform when released. Especially on the 2MB cache models, since I'm guessing the single cores won't bust out the door with a full 4MB.

    Just some food for thought/consideration. I personally would love to see a few tests run this way and compared to some single/dual core A64's.
    Reply
  • JarredWalton - Friday, July 14, 2006 - link

    Conroe-L is so far off that it's really an afterthought. The only reason it's not shipping is that Intel has a ton of Netburst stuff to offload, IMO. At $145, the PD 945 is still interesting in terms of certain computational tasks. (I miss the QMD Folding@Home cores....) Reply
  • fishbits - Friday, July 14, 2006 - link

    I had hoped AMD could gain even more market-share before something like this happened, would rather see the two CPU makers on more even footing. Intel just hit this one out of the park however, if pricing holds and availability is decent. Was looking at upgrading my 3500 (939) to a $300 X2 4600 after the price drop, but now? It looks like I'll probably keep this system and build a new rig around a $300 Intel 6600, which wins over or smokes the 4600 depending on benchmark. I really don't know what AMD can do to keep me in the short term, because I don't know if they can make any money dropping prices as far as it looks like they'll need to go. Reply
  • SpaceRanger - Friday, July 14, 2006 - link

    One thing to consider though, if you decide to go with the C2D 6600, then you will also have to spend $$ on a new Mobo + Memory (since your DDR RAM won't work on the platforms for C2D. Keep that in mind when you're upgrading. Reply
  • fishbits - Saturday, July 15, 2006 - link

    When I said that if I went with Intel I'd keep my current rig and build a new one around the Conroe, didn't it dawn on you that I'd already "considered" the need to get a new mobo, memory, etc? Reply
  • SpaceRanger - Sunday, July 16, 2006 - link

    Holy arrogance.. EXCUSE ME for pointing something out.. Reply
  • epsilonparadox - Friday, July 14, 2006 - link

    Well the loads of money they made when they had the better performing architecture can hopefully keep them doing very well also the Opteron isn't really being challenged and thats really their moneymaker right now. They shouldn't have any problems lowering prices on their desktop chips while keeping the status quo on the Opterons. Reply
  • zsdersw - Saturday, July 15, 2006 - link

    They can't really keep the status quo on the Opterons either. Woodcrest excels (or, at the very least, is equal to the Opteron) in the 1P and 2P server space.. which is a huge chunk of the overall server market. Reply
  • LoneWolf15 - Friday, July 14, 2006 - link

    While I'm sad to see AMD lose the performance crown, I'm not so obtuse as to deny it's happening.

    I'm excited by Intel's newest chip, but I think the results for me will be that I'll buy a faster Athlon 64 X2 when the prices drop (assuming Socket 939 ones become cheaper as well, I don't plan a move to Socket AM2 for some time to come). So Intel's newest chip should benefit even those of us sticking with an AMD system. :)
    Reply

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