Help With Catalyst Control Center overdrive feature

Hi everybody,

I'm running an ati radeon 7870 with CCC 12.1
I just tried to use the overdrive feature and maxed out the clock settings (maybe not the best idea?) and my display just shut down, had to restart my computer. It works with only one window open, but running more applications is out of the question on overdrive.
Could you help me point out what I'm doing wrong (probably everything).
Thanks.

Other Specs:
Intel i5 3470 3.2Ghz
Windows 7 64 bit ultimate
16gb ram
Asus ASUS P8Z77-V LK Z77 MB i think
Let me know if you need anything else