PC not getting enough power?

[TehTotalPwnage]

Sorry if this is off topic, but I really need help with this.

So I ran over to Fry's Electronics to grab an Antec HCG-620M to use as a power supply, even if temporarily. This is to replace my old Zalman ZM500-RS which couldn't provide enough power on the 12V rail to power my EVGA GeForce GTX 760 Superclocked ACX. However, new issues popped up. Now, if I try running FurMark power throttling is an issue rather than temperature limits. In addition, there are a ton of FPS drops to 0 in FurMark, usually when I hit 99% TDP. There's also an issue with my In addition to this, I've noticed my room light which is connected to the same outlet as my PC flickers at about the same time my FPS drops in FurMark.

This probably isn't the clearest question, but what is causing my power issue? I've heard about faulty power outlets, but I'm not sure if that's the issue.

[thekeemo]

its called bad house wiring 

[Ex0Thermic]

normally your pc world crash or restart if it was not getting enough power (worse case the psu would pop).

I would say there is another fault causing your issue.
if you are sure that nothing is overheating then you might want to run memory test, check disk on hdd's

or maybe even try reinstalling windows as it might be a corrupt software/drivers too.

[Spanx24]

It's the power outlet and it's really easy to troubleshoot...  Go plug your PC into an outlet in a different room in the house, or better yet, do it at a friend's house.  It's highly unlikely to be a HDD or software/driver issue...

[mlbguy4life]

if the lights flicker in your house, it usually means that you dont have a good ground, but yeah if you dont have enough power from the outlet the pc should crash or cut off i would think.