Did you raise the voltage on your GPU?
What are you using to cool the i7? How hot do the temps get all loaded up?
What did you set your vcore at for your 4.5ghz setup?
My vcore was 1.35
If you go into your BIOS and set your LLC to 2 you should be able to drop the voltage* - good for temperatures and power consumption.
*stolen from 87dtna