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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  • mino - Wednesday, May 24, 2006 - link

    Well, IMHO the point is AMD has used exclusive 3-level cache structure in the past so they have som experience with thi arrangement. Reply
  • Questar - Tuesday, May 23, 2006 - link

    No flame here, look it up for yourself.

    Z-RAM has high capacitive loading, which results in slow speed.

    At 4MB it'll run half the speed of SRAM.
    Reply
  • Questar - Tuesday, May 23, 2006 - link

    Large amounts of Z-RAM are pig slow. Reply
  • Ecmaster76 - Tuesday, May 23, 2006 - link

    Seriously, the one area an Athlon X2 would be bandwidth starved and does it get tested in the preview? NO
    In the review? NO

    How long ago did we know that the K8 was not bandwidth limited in single application usage? YEARS


    So yeah, DDR2 din't increase the 3dMark, big surprise
    Reply
  • mlittl3 - Tuesday, May 23, 2006 - link

    I think 3dMark06 is multithreaded now so all available cores and bandwidth should be used within the limits of the program. I could be wrong about this however. Reply
  • Ecmaster76 - Tuesday, May 23, 2006 - link

    3Dmark06 is almost completely GPU limited. The 3Dmark CPU score did increase a bit, but I really was referring to graphics benchmarks in general. Reply
  • cscpianoman - Tuesday, May 23, 2006 - link

    I was just noticing the performance differences between the FX and the EE. In some cases the FX tromps the EE by "gasp" 30%! In other cases the EE makes it's mark. This is part of the reason I am skeptic on Conroe. Yeah it's good. But I always take what Intel, or AMD for that matter, with a grain of salt. Just today we saw the 30% advantage translate down to about 15%. This seems just like any other generation change where 15% is to be expected. The current hype for the Conroe is a product of Intel's excellent marketing dept. Reply
  • mlittl3 - Tuesday, May 23, 2006 - link

    Until K8L (which will have microarchitectural improvements), there are a few things that could allow AMD to look good against Core 2.

    1) Price drops so that comparable K8 and Core 2 processors are the same price giving the same performance/$ ratio (this metric is important for the budget constrained)

    2) Nov. '06 release of 65 nm AM2 processors so that K8 and Core 2 processors will have the same performance/watt ratio (65 nm could give K8 a 20% drop in power and with Core 2 being 20% faster, they will have the same performance/watt ratio which is popular now). Also, everytime AMD transitions to a new die process they add some minor bug fixes and minor memory/microarchitectural enhancements which could also boost performance by a few percent.

    3) Continual improvements to DDR2 latency might yield a 2-2-2 DDR2 800 memory module which will probably benefit K8 more (maybe ~5% improvement) than Core 2 but this is a wild guess here and I don't know if it is even possible. However, DDR400 latency started around 4-4-4 and dropped to 2-2-2 so it could happen.

    With the same performance/price and performance/watt as Core 2, K8 could stay competitive and OEMS and users decide on which company (if not both) they would like to do business with. This is all speculation and of course everyone is more than welcome to rip my reasoning to death.
    Reply
  • JarredWalton - Tuesday, May 23, 2006 - link

    I seriously doubt we will ever see DDR2-800 running at 2-2-2 timings. (Feel free to quote me on this in the future and make fun of me if I'm proven wrong. :-)) Just think how long we had DDR memory around, and no one ever managed to create 1-1-1 DDR-400 memory. I do think we will see 3-3-3 DDR2-800, and possibly even higher bandwidth with those timings. In fact, we almost have that already judging from my experiences so far with socket AM2. (I can post and run benchmarks, but I wouldn't call the system 100% stable.) Reply
  • mlittl3 - Tuesday, May 23, 2006 - link

    LOL! I will! Reply

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