Ok, I use the same CPU in my main computer right now. As you can see in my sig, I have it at 2.7GHz, but I have the benefit of very overclockable ram.
I do believe it's likely the ram that's holding you back. Under the BIOS, you will see various CPU/RAM dividers, like 1:1, 10:9, 5:4, et cetera. This means that the CPU and RAM will work on a divider.
Say for instance you choose 200HTT, which would result in a 2.0GHz CPU and DDR400 speeds. If you choose the 5:4 divider in this instance, it would mean that the CPU would still be 2.0GHz, but the ram would be approximately DDR320:
200 / (5/4) = 160MHz (* 2 = DDR320)
So, if your RAM is holding you back, then as you increase the CPU GHz, you will need to lower the divider, to make sure that the memory is not going to go over DDR400. Or... you could try increasing the Vdimm, but I wouldn't go far above 3.0v without a fan on the ram.
You can use that CPU-z program to keep track of your ram speeds, under the tab there. Just multiply the MHz by 2 to see what your real "DDR" speed is.