Athlon64 CPU Heat - Venice vs. San Diego

[sipitai]

Hi everyone,

I would like to know if there is any difference between the amount of heat generated by an Athlon64 3500+ CPU (Venice core - 512KB L2 cache) and a 3700+ (San Diego core - 1024KB L2 cache), given that they both run at the same speed (2.2GHz) and the only difference between the two cores (as far as I know) is the size of their L2 cache?

I am considering buying the 3700+, instead of the 3500+, but only if it does not generate any additional heat.

On a slightly different topic, I would also be interested to know the difference between the amount of heat generated by a 3000+ and a 3500+ (both Venice cores).

I have been googling this on and off for a few days now without any luck, so any information anyone has to offer on this subject would be greatly appreciated.

Thanks!

[frostedflakes]

The San Diego core does consume more power than Venice, although I don't think the difference is very significant. I can't seem to find any Venice vs. San Diego power consumption charts, but here's a Newcastle vs. Clawhammer (basically the 130nm Venice and San Diego) chart. Should at least give you an idea of how much of an impact cache has on power consumption. The 1MB L2 Clawhammer core consumes ~16% more power than the 512kB L2 Newcastle core at idle. At load the difference seems to decrease. I think it'd be safe to assume the San Diego and Venice follow a similar trend.

http://www.lostcircuits.com/cpu/amd_venice/7.shtml

As for the 3000+ vs. 3500+, keep in mind that power consumption and clock speed are linearly related. In other words, if you double clock speed, you double power consumption. The 3500+ is 22% faster than the 3000+, so it will consume 22% more power.

(FYI, the relationship between power consumption and voltage is exponential -- if you double voltage, you quadruple power consumption; if you cut voltage by 1/4 [which is a pretty reasonable undervolt for a 3000+ Venice], you cut power consumption in half!)