Yea what's holding you back is you're overclocking the memory too high. With my memory running async (3:2) set to 800Mhz @ 3.2Ghz my memory was overclocked to 960Mhz which was as fast as it would go!
I'd drop the divider to 4:5 (667) and that will give you more headroom. That's what I did.
If you need more headroom still, drop the memory divider again lower.
You really don't need to wait for the Thermal paste to set totally before you start overclocking, but watch your temps until it's totally set.
And if I'm wrong about any of this, anyone that wants to can jump in and correct me! I've been known to be wrong before...
