Our test OS was Windows Vista Ultimate SP1 with ATI Catalyst version 8.9. Power consumption was tested with an Extech Power Analyzer measuring system wattage.

Our idle power measurement was taken 5 minutes into Windows Vista desktop idling the computer. Load was with all four cores at 100% in task manager using Valve's map creator benchmark to stress the CPU fully. C'nQ recognizes Cool 'n Quiet enabled. We tested these processors multiple times and found at least in our specific CPUs basically no difference between our 140W Phenom 9950 BE and our 125W Phenom 9950 BE in regards to power consumption. We weren't expecting a large difference given the only 15W maximum difference in rating between the two processors but we basically saw none in all instances of testing. One thing we do see is Cool 'n Quiet save about 25W at idle.

We spoke with Damon Muzny at AMD about this and he told us that there will be variation in processors in power consumption between processors even of the same model which if graphed would create a bell curve. Looking at just these two this might have been a 140W Phenom 9950 that was towards the lower-end of power consumption and a 9950BE 125W which was towards the higher-end. Somewhat similar to how no two processors will overclock the same there will be some variance in power consumption between two processors. So looking at only two might show nothing but if you took 100 of each and tested them you should see a bell curve appear with more variation between the processors. Additionally AMD might have been cautious in their rating for the Phenom 9950BE 140W.