Overclocking

[Woppet*]

Ok basically i'll post here what i posted /g/

I just bought an Asus 1GB GeForce GTX 560TI DirectCUII PCI-E

The rest of my specs are in the attached image.

I have literally no experience with overclocking and i was wondering if you guys could help me.
I downloaded afterburner like a friend told me to and the defaults were as pictured.

I followed an OC guide for my card which told me to set the values to 1GHz for the core, 2GHz on the shaders and 1200MHz on the memory.

However after doing this i didn't notice any raise in FPS in the games i tested (GTAIV, Skyrim and WoW) But i did notice big slowdowns on occasion, and one instance where wow's fps shot up to 1000 before immediately crashing. I've also experienced windows freezing multiple times.

Do any of you guys know what i should set the values to to get everything running smoothly again? Is there some huge problem with my hardware that's preventing me from OCing effectively?

Thanks in advance guys i am seriously stumped with this and i have literally no idea what to do.