So, I finally ran this 3D Mark thing
At 600/450 clocks (can't get to 400 on memories as the 4550 is equipped with GDDR3 which can't clock that low) my score is 2543
, though I have an E8400 clocked at 3,6 GHz so this should have improved the score a bit. Clocking the memories to the maximum stable value, which is 873 MHz, I got a much neatier 3954
points, which is already higher than your 4650, showing that this tight memory bus is really the limiting factor. In fact, by going haywire on the core at 745 MHz the improvement is much less pronounced, getting to 4334
So, the bottom line is: I did a good thing by going for a 4550 instead of one of those crippled 4650, as it turned out to be a higher performing card when overclocked.
Corsair HX750W - My personal experience
Nothing thermaltake makes is ever quiet. If they could figure out how to make a flash drive noisy, they would.