Faster timing and the (probably) higher DRAM bus voltage puts a greater load on the memory controller located inside the CPU.
My opinion - the very little real performance gained is not worth the higher temps. The higher temps will act as a limiting factor on your overclock which is where the real additional performance comes from.
I brought the memory to auto, and dropped the DRAM FRQ to 1433...temps dropped on idle almost 10 deg...
If i could ask could you to recommend a setting that is optimal and acceptable ...I have a Geforce GTX 590...and the CPU as you know is running at 3.6Ghz at 180x 20 Vol 1.2750
What should i drop either QPI Frq or ratio or the voltage...i would like to bring the temp even lower but not to low that it bottlenecks with the vga. I could try to bring the voltage to 1.25 but i dont think it will carry 3.6Ghz.