I made an account just to let you know that i am running the exact same motherboard/CPU and also a GTX 560. I recently upgraded from a GTX 260 that had more or less died on me.
After some research before buying the GTX 560 i was told that i wouldn't see much of a perfomance boost as my Q6600 would hold me back. Well was they wrong!
Put it this way when i played Dirt 3 for instance on my older GTX 260 on DirectX 9 and all medium settings i was lucky to see the FPS hit 60. Now with my GTX 560 on DirectX 11 and maxed settings the FPS never goes below 75. And the temps of this card are like half of what the GTX 260 run at.
Anyway on to your problem. If you are running the Q6600 at it's stock speed of 2.4GHz then the CPU is bottlenecking you GPU. You can easily reach 3.0GHz overclock with the Q6600 on stock cooling, and providing your whole system has ample airflow too. 3.6GHz on a custom cooler with ease also. But i run mine at 3.0GHz with a Tunic Tower 120 cooler and to this day (Touch wood) have never had a single issue.
Going from one graphics card to another and seeing no change in perfomance, FPS etc is a well known tell-tale sign of bottlenecking.
If you need the settings for your bios for say an 3.0GHz overclock i would be more than happy to pass them over.
Also if you are already overclocking then there is obviously something else not right somewhere.
I hope this helps you out in some way.
Ahhh! Just noticed in one of your earlier posts:
Originally Posted by Szat
Might sound weird, but does my CPU being 5% overclocked matter at all? I only ask because on a forum I was reading someone said make sure the CPU is stock clocked before installing the drivers.
Not sure what the 5% Overclock is (2.5GHZ?) If so then it's not enough for the GTX 560. Another thing to keep in mind is a lot of the settings in the bios require manually setting instead of Auto settings. This goes for most motherboards as auto settings a lot of the time under volt the components.
Like i said anyway i have a rock solid stable 3.0GHz overclock so if you want the settings just gimmi a shout