Thanks for reply!

I found a "solution" to my problem.

I figured out that my multiplier on motherboard was set to x8 when It should be x9. Therefore Quad wasn't working at full performance.
It is smooth now ;)

---------

I assembled my PC six months ago. i7 was far away my price range so I decided to assemble a pc with quadcore.
Q6600 has great ability to OC.
Motherboard has heat pipes and special protection against short circuit. What's more there is still place for 1 memory module.

I think I need to max out this configuration before I will buy next PC.

---------

To anybody who is searching for better frame rate in 727's VC:

Sorry, there is no easy way to increase it significantly, update your hardware.

Topic closed.