If you are concerned about the PSU you have and its ability to handle overclocking, I have to be honest and tell you that it most likely is hindering the ability to reach what would otherwise be your maximum potential. However, it isn't a matter of raw output being too low. It's an issue with providing your components with clean, stable voltage. You can get a summary of what I mean here: http://www.hardwaresecrets.com/article/Cooler-Master-GX-750-W-Power-Supply-Review/917/10.
You could go back a couple pages in the review to see the noise and ripple test results. Compare that to a unit like those sold by Seasonic and you'll see the difference in the graphs is night and day.
Nothing worries me more than seeing a very nice system like yours, then seeing that it's being trusted to a power supply that legitimately poses the risk of killing any or all of the vital components.