Power Consumption

Given that AMD reduced power consumption a bit alongside the move to Socket-AM2, we wanted to see how the new chips compared to the latest CPUs AMD had sent us prior to the launch. So we pitted our last Socket-939 sample, the Athlon 64 FX-60, against the two new Socket-AM2 samples we just received: the Athlon 64 FX-62 and the X2 5000+. Remember that the FX-62 actually carries a 125W TDP rating, so it shouldn't be any cooler than previous CPUs, but the X2 5000+ is a new 89W part.

There are inevitably going to be power differences between the Socket-AM2 and Socket-939 motherboards we used, but unfortunately there was no way to isolate them from the comparison as we are measuring total system power consumption.

System Level Power Consumption at Idle

System Level Power Consumption under Full Load

Under full load, the X2 5000+ does appear to be a bit cooler than the Socket-939 FX-60. We've seen in the past that the 1MB vs. 512KB of cache doesn't really result in any significant difference in power consumption, so it looks like the overall decrease in power consumption is because of the improvements in production AMD has implemented at Fab 30. It is worth noting that the Pentium Extreme Edition 965 consumes just as much power as the FX-62, thanks to its 65nm manufacturing process. Even so, we still can't wait for Intel to drive its power consumption levels even lower later this year.

The Odd Multiplier Issue Final Words
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  • Furen - Wednesday, May 24, 2006 - link

    Also, having all that extra bandwidth available allows AMD to throw quad-core on the same socket without much problem (maybe 1H07... whatever everyone says I doubt AMD will let Intel have the quad-core advantage for a year, I'd say we'll see very low volume quad-cores as close to Intel's Kentsfield/Cloverton as humanly possible). I know we've heard that AM3 is coming next year (from, who else?, The Inquirer) but considering that the DDR3 spec is not finalized quite yet and just how slowly AMD jumped into the DDR2 bandwagon I'd say we won't see it until 2008 at the earliest. Reply
  • Axloth - Wednesday, May 24, 2006 - link

    I think there is also marketing side. There are lots of people "unaware" of ddr1-ddr2 comparison. And they probably think that ddr2 "must" be better than ddr1 because of that that "2". Like: ddr2 is upgrade or next generation of ddr1 so its gotta be much faster. Also, they might go for intel because intel uses ddr2 and amd only ddr1... And they think intel's better thanks to ddr2, disregarding cpu qualities of both amd and intel. Reply
  • pzkfwg - Tuesday, May 23, 2006 - link

    If DDR2-800 barely beats DDR-400, I was wondering if the AM2 socket could actually be slower than 939 DDR-400 when using DDR2-667 !?! Knowing that a very large amount of people would buy cheaper AM2 system with DDR2-667, that would be ridiculous! Reply
  • mino - Wednesday, May 24, 2006 - link

    YES and NO.

    Remember most people buy generic CL3 or CL2.5 DDR400. IMHO generic DDR2-666 should be ona par with that.
    Reply
  • soydios - Tuesday, May 23, 2006 - link

    So, the X2 4200+ will not run the memory at full speed. How safe would it be to overclock from 200x11=2200MHz DDR2-733 (2200/6=366x2=733) to 219x11=2200MHz DDR2-803 (2409/6=401.5x2=803) using OCZ DDR2-800 RAM and an Asus Xpress3200 motherboard? Reply
  • Furen - Wednesday, May 24, 2006 - link

    I'd say that you can very likely get away with that overclock with pretty much every 4200+ as long as the motherboard allows you to do it. Reply
  • mino - Wednesday, May 24, 2006 - link

    Safe as safe. At least from the point it won't blow up :)

    As for stability it all depends on the motherboard.
    Reply
  • peternelson - Tuesday, May 23, 2006 - link


    I see no benchmarking in 64 bit mode.

    This is the future, and for maths, Intel's 64 bit was more of a lame copy of AMD 64 bit performance.

    In future this will be increasingly important so even if 32 bit performances are comparable, I'd want to make sure the picture is the same running 64 bit apps.


    Also you summarise "same performance, faster memory, less power". True, but you FORGET one of the main benefits: Pacifica Virtualisation.

    True hardware virtualisation adds to the actual WORK you can keep that processor busy with. It saves time by letting you switch OS instances without rebooting timewasting.

    As it is hardware based VT you should even be able to virtualise an UNMODIFIED OS like Win XP, maybe even Vista!

    So please play with Xen3.

    As you say virtualisation "works" then it is a BIG factor for me in choosing AM2 over 939, (all other things being equal).

    Also the fastest 939 chips have been produced, and AM2 is reaching higher models now.

    So if you want the VERY fastest, it is only available on AM2.

    Don't forget: Not just performance, but performance PER WATT. For these AM2 chips that is similar to 939.

    However, the announcement of 65W EE and EVEN 35W SFF EE!!! are significant compared to the standard 89W

    Intel seem to be positioning Conroe as being "33% better" on performance per watt. However, Conroe isn't even here but when it is, it may not be able to compete with AMD low power offerings.

    Also consider the whole system for conroe vs AMD. Because that AMD power INCLUDES the memory controller, whereas Intel doesn't. The whole motherboard etc may use less power.

    Also in terms of entire system cost, motherboards for AM2 appear to be a bit cheaper than their Intel equivalents, which may offset the current high prices of AMD processors.
    Reply
  • fitten - Wednesday, May 24, 2006 - link

    You should check out the Woodcrest (server targeted Conroe core) previews for power measurements. Performance per Watt, Woodcrest wins (and will be available in 3 weeks)... Absolute power usage under load, Woodcrest wins... and note that the power measurements are for the complete system (video card and HDDs included). (Deep power conservation couldn't be tested on Woodcrest because the parts didn't have it enabled as they were engineering samples.)

    Also, check out the 64bit vs. 32bit comparisons in programs like Cinebench 9.5. Seems Woodcrest 64bit gives a nice boost there (showing that it isn't just a 'lame copy').

    You also seem to forget that Intel already has virtualization extensions out in currently shipping processors (much less Conroe+).

    As far as price, there have been price lists published already. High end Conroe parts are already listed for 1/2 the price of the high end AMD parts... at $500 that gives another $500 for purchase of a motherboard before it touches just the CPU cost of the AMD... I doubt that the motherboards will be that expensive.

    I have 7 AMD machines (four are Athlon64s or X2s) but right now, it looks like my next machine will be a Core2 one. AMD needs to get an answer out... soon. K8L isn't going to cut it. Sure, it'll be good at FPU but the vast majority of work done by CPUs is integer, which are what the majority of improvements are in Core2 (not that they don't have good FPU improvements). So, if you're in a government lab running FPU intensive simulations, K8L may be for you. If you're anyone else, K8L as it has been described looks kind of anemic and not a match for Core2.

    Maybe the real K8L will surprise us, who knows, but it is at least 6 months away (if not longer). By that time, Intel will already be 25% into it's 2-year cycle for the next Core derivative chip (probably farther, time between releases is set to 2-years). AMD looks to be in a bad situation right now... If they have something they're keeping secret, IMO, they need to at least tease us with it. K8L is not a tease, it's only slightly more than a stifled yawn. The longer they go without giving us something to look forward to, the more it looks like they are in major trouble.
    Reply
  • Accord99 - Wednesday, May 24, 2006 - link

    [quote]Don't forget: Not just performance, but performance PER WATT. For these AM2 chips that is similar to 939.

    However, the announcement of 65W EE and EVEN 35W SFF EE!!! are significant compared to the standard 89W

    Intel seem to be positioning Conroe as being "33% better" on performance per watt. However, Conroe isn't even here but when it is, it may not be able to compete with AMD low power offerings. [/quote]
    Given that Woodcrest 3.0GHz has a TDP of 65W, which is borne out by power measurements conducted by Techreport and 2CPU, it's likely that a Conroe that matches the performance of the 35W X2 will at the very least, also match it in power.
    Reply

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