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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  • 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
  • soydios - Tuesday, May 23, 2006 - link

    AMD motherboards are less expensive because they don't have to put in a memory controller.

    AMD processors are more expensive for 2 reasons:
    - integrated memory controller takes up more die space (offset by cheaper motherboard)
    - AMD is still using 90nm on 200mm wafers, while Intel is using 65nm on 300mm wafers (Intel gets more CPUs per wafer bigtime)
    Reply
  • peternelson - Tuesday, May 23, 2006 - link


    Sempron AM2 can do memory up to DDR2-667

    Dualcore AM2 can do memory up to DDR2-800

    However, PLEASE CHECK SINGLE CORE MEMORY SPEED (multiplier issues aside) which you say limited to 667 whereas I got the impression they can also do 800 like dualcores. Correct as necessary.
    Reply
  • smitty3268 - Tuesday, May 23, 2006 - link

    I accidentally hit the "not worth reading" button, so I'm writing this comment to undo it :) Reply
  • fikimiki - Tuesday, May 23, 2006 - link

    There are a couple of reasons for that:
    - K8L photo had a Z-RAM implemented, so they are using this kind of cache for a quite long time.
    - Shared L3 should help Athlon64 in matching Super-Pi and overall performance.
    - Usage of Z-RAM will reduce cache die size by 75% with no architectural changes.

    So FX-64 to beat fastest Core 2 just needs 4MB of cache...
    Easy trick but can be useful to survive till 65nm production...
    Reply
  • Questar - Tuesday, May 23, 2006 - link

    quote:

    K8L photo had a Z-RAM implemented, so they are using this kind of cache for a quite long time.


    It's not going to be Z-RAM. Z-RAM won't even be in K8L.

    “We’ve looked at data from Innovative Silicon and it looks very promising. We still need to assure ourselves that this will work in our own application. We need to see how it scales and we need to make our own test vehicles,”

    Jones, an executive experienced in intellectual property licensing, also declined to comment on AMD’s timetable for introduction of Z-RAM but offered a more general perspective. “In the past it has been two years from when you sign a deal to when it is in production.”


    http://www.eetimes.com/news/latest/showArticle.jht...">http://www.eetimes.com/news/latest/showArticle.jht...
    Reply
  • munky - Tuesday, May 23, 2006 - link

    I think the June trick AMD will pull out is the Clearspeed coprocessor. It definitely won't affect many users, but for those who do invest in the technology, it could provide a decent boost in number crunching power. Reply
  • peternelson - Tuesday, May 23, 2006 - link


    Clearspeed are working on being one acceleration solution, yes, but the already launched acceleration on socket 940 is companies offering plug in Xilinx4 FPGA on hypertransport.

    I hope that gets re-engineered onto socket F pretty quickly. We may see announcements once socket F is actually launched in July.
    Reply
  • darkdemyze - Tuesday, May 23, 2006 - link

    z-ram isn't due for AMD procs for quite some time, I doubt this is their plan for June.. Reply

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