So my OC results are a bit disappointing. To be at all stable in Heaven, I can only OC the core by +100 (2100 Boost clock) or OC the memory by +300 (4300MHz), doing both causes instability. Interestingly, the Memory OC gets my about 10% better results in Firestrike, while Core OC gets me 10% better in Time Spy.
This is with 122% Power Target, 100% Voltage (tops out at 1.094v with the memory OC). No throttling though, which is good.