Power Consumption and overclocking

Power Consumption

The newer AM3 Phenom II X4 processors have a pretty good TDP (peak wattage), compared to the last flagship products they shaved off 20 watts while increasing performance. For this review we used and tested with the Phenom II X4 955BE processor that has a TDP of 125 Watts (= 125W peak, when all 4 cores in the processor are 100% utilized and stressed).
Much like the last-gen products, we have four active and independent cores here. Each core can be clocked down independently if not utilized, saving heaps of current. If the cores are temporarily inactive, they can pretty much put themselves in sleep-mode (clocking down). Hyper Transport will power down and a low-power stage is activated on the memory.

AMD's Cool'n'Quiet technology was recently updated to revision 3.0 and provides even better power management. Keywords here are improved power tuning with additional performance states, and up to 50% less power at idle compared to Cool'n'Quiet 2.0

As a result we notice our test platform peak out at roughly 180 Watts power consumption when we stress the CPU cores. Our system however idles merely at 129 Watts (dedicated graphics card used, not an integrated one).

We used an 785G based AM3 motherboard and added a dedicated graphics card (GTX 280), you'll notice that the end-result overall in idle and peak wattage is very impressive.

As you can see once we stress four CPU cores with Prime95 (stress test), our power consumption maxes out at roughly 185 Watts.
 

Overclocking

If you decide to start an overclocking session with the Phenom processor; typically you are much better off with the BE editions (CPU multiplier unlocked). In today's test we will overclock the Phenom II X4 955BE (Black Edition = easy to overclock).

The key to the 770/790FX/GX and thus now 785G feature set is AMD's Windows compatible Overdrive interface that allows very easy overclocking of the Phenom II (and last gen Phenom X4 Black Edition) processors. It's one of the best tweak utilities out there and thanks to AMD's recently introduced Advanced Clock Calibration technology the results on a 770/785/790 chipset based platform will certainly be good.

For this review we used a new 3.0 beta which has some cool new options.

• Download AMD Overdrive here

In AMD Overdrive you can simply max out the CPU voltage towards ~1.50V and increase the multiplier. Play around with it, don't be afraid of a crash.

Here's what we did though. With a simple OCZ Vendetta 2 35 USD air-cooler we reached 3700 MHz 100% stable within 4 seconds. If you use a decent cooler or even better, water-cooling... 3800-4000 MHz should not be an issue. These are very common tweak frequencies for AMD Phenom II processors.