Yellow versus Red?

In complete reflection of the previous results, while there is the odd result where the yellow mode suffers quite considerably against the faster red, generally speaking its minimal or non-existent difference. This is to such an extent that we'd opt to leave the turbo mode set to yellow in AMD's Overdrive software.

The power savings (below), and hence cost and noise, are certainly worth it. We found it does automatically set itself to red when overclocked which does add to the considerable heat output, but not including the power saving optimisations should make the CPU overclock better.

This is something Intel CPUs should learn to do automatically as it helps keep them stable when they are pushed – I'm sure at some point we've all forgotten to disable EIST/C1E in the BIOS then wonder why a board isn't hitting the clocks we had expected it to.

Power Consumption

We used the same Corsair XMS2 8500C5 Dominator memory and Nvidia GeForce 8800 Ultra in both AMD and Intel systems to maintain consistency. Extra cooling fans were removed, except for the CPU cooler.

BIOS settings were returned to default on both boards and AMD Cool'n'Quiet and Intel EIST/C1E states were enabled, however AMD's "Turbo mode" was left enabled and we tested both yellow and red to show the difference for the B3s.


While the yellow mode doesn't seem to affect upper end power use, it does significantly affect the idle power, saving some 30W on average. The B3 Phenoms are considerably more power hungry at the wall socket, with both idle and load increasing quite significantly even on a clock to clock comparison: 9550 versus 9500, in the "yellow" mode the 9550 might be 7W more efficient, but it's also 36W more inefficient at load. Both have a 1.8GHz northbridge and HyperTransport and 2.3GHz core clocks. The 9850 peaks at over 300W, which is only 7W more than the Intel Q6700, however the Q6600 which is relatively close in performance is 22W more efficient under load and 58W more efficient when left idle.