How do i know if power supply is my problem

[Birthrulz]

Hello,
I just bought my new computer with specs,
I7 3770K 3.5Ghz
16MB Ram
GTX6600Ti
Is power supply 650w enough to power my system normally, cause im having some problems that my system is restarting when i try to run 3D mark 11

 

[Wisecracker]

Download and do a one hour run of OCCT. Be sure to enable *Graphs* from the Options menu.

After the run, a window will open with a series of graphs showing power delivery over the time of the test and your level of ripple.