HD7850 OC results:
HD7850 1050: 1m 40.599s
Device time for pi calculation: 99.495 s
Device time for memory reduction: 1.104 s
HD7850 1100: 1m 36.056s
Device time for pi calculation: 94.996 s
Device time for memory reduction: 1.059 s
HD7850 1125: 1m 33.919s
Device time for pi calculation: 92.902 s
Device time for memory reduction: 1.018 s
1150: 1m 31.845s
Device time for pi calculation: 90.859 s
Device time for memory reduction: 0.985 s
- video driver restarted
1175: 1m 30.347s
Device time for pi calculation: 89.266 s
Device time for memory reduction: 1.081 s
1175 w/ 1400 ram: 1m 30.305s
Device time for pi calculation: 89.227 s
Device time for memory reduction: 1.078 s
1200: 1m 28.413s
Device time for pi calculation: 87.370 s
Device time for memory reduction: 1.042 s
1225: 1m 26.624
Device time for pi calculation: 85.590 s
Device time for memory reduction: 1.034 s
I tried various memory overclocks ranging from stock (1200) to 1700mhz and found improvements to be within margin of error.