Power Consumption

Idle Power Consumption

Without power gating the Athlon II X4 draws as little power as possible, noticeably less than any of AMD's other multi-core CPUs. Our X4 620 sample was a bit more power hungry than our 630.

Load Power Consumption - x264 HD Bench Pass 2

Even under load the power consumption story is a good one. Given the position of our Q8400 sample here we'd say that the Q8200 would probably use a bit less power, but the price differential should more than make up for it.

Overclocking

As I mentioned at the start of this article I managed to hit 3.25GHz on the Athlon II X4 620 without any additional voltage using the retail AMD cooler:

I could hit 260MHz x 13.0 for 3.38GHz by upping the voltage, but the gain wasn't worth the additional power usage. Anything higher wasn't possible without more exotic cooling or much more voltage. The performance improved handily at 3.25GHz:

Processor Adobe Photoshop CS4 x264 2nd pass Left 4 Dead
AMD Athlon II X4 620 (2.6GHz) 27.5 seconds 15.4 fps 93.2 fps
AMD Athlon II X4 620 @ 3.25GHz 23.2 seconds 18.9 fps 102.9 fps
AMD Phenom II X4 955 (3.2GHz) 22.3 seconds 19.1 fps 121.4 fps
Intel Core 2 Quad Q8400 21.8 seconds 17.9 fps 105.6 fps

 

At 3.25GHz the Athlon II X4 ends up faster than the even more expensive Q8400in some cases, and gets much closer in others. In applications where the large L3 cache isn't missed, the overclocked Athlon II can end up being a poor man's Phenom II X4 955. But looking at the Left 4 Dead performance, there's no such thing as a free lunch - the overclocked Athlon II isn't quite that good.

Gaming Performance Final Words
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  • Eeqmcsq - Wednesday, September 16, 2009 - link

    The L2 cache in the Athlon II X4s are the same as the Phenom II X4, 512KB per core, 2MB total. It is only on the Athlon II X2s that the cache was doubled to 1MB per core, 2MB total.
  • TA152H - Wednesday, September 16, 2009 - link

    Oh, OK. I guess I should actually read the charts.

    Thanks.

    Hmmmmm, I wonder why they overclock so poorly. It doesn't make much sense. You'd think it would use less power, and generate less heat. Strange.
  • Anand Lal Shimpi - Wednesday, September 16, 2009 - link

    Two options: 1) New die, takes time to get the mix perfect for better yields/higher clock speeds, or 2) the chip isn't using super high frequency/high leakage transistors to maximize performance. It could be designed to hit lower frequencies.

    Take care,
    Anand
  • Eeqmcsq - Wednesday, September 16, 2009 - link

    The skeptic in me says bad design problems, like the first Phenoms. That could also account for the multiple delays and pushbacks on the Athlon X4s. But in all seriousness, I have no idea.
  • Eeqmcsq - Wednesday, September 16, 2009 - link

    Found this on another site. Perhaps you can check and confirm:

    "...the imprint "AADAC” identifies the CPU as a Propus."
  • Anand Lal Shimpi - Wednesday, September 16, 2009 - link

    My 620 is an AADAC while my 630 is an AACYC. I will ask AMD to confirm :)

    Take care,
    Anand
  • Anand Lal Shimpi - Wednesday, September 16, 2009 - link

    Spoke with AMD this morning. The OPN does not indicate whether or not the chip has a disabled L3. It's just luck of the draw, there's no way to tell by looking at the chip itself.

    Take care,
    Anand
  • Doormat - Wednesday, September 16, 2009 - link

    Please upgrade to a more modern x264 benchmark. I'd recommend a recent handbrake snapshot (http://handbrake.fr/snapshot.php)">http://handbrake.fr/snapshot.php). The nehalem optimizations should boost performance dramatically and are a better representation of what people would get with current encoders.
  • Anand Lal Shimpi - Wednesday, September 16, 2009 - link

    I agree completely, the question is more one of when we make the transition. There's a lot of historical data we need to compare to. You'll see a slow transition to new tests especially with the final version of Windows 7.

    Take care,
    Anand
  • Lunyone - Wednesday, September 16, 2009 - link

    Finally we have quad cores at about $100!! Hope that this will spur on better pricing on all fronts! Go AMD, we need the competition to drive down better pricing. Now only if you would drop down the PhII x4 955/965 pricing to compete better with the i5 750!!

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