To overclock the Powercolor card today we used Catalyst Control Center initially, then pushed higher with the Sapphire TRIXX overclocking tool. All of our samples overclocked to almost identical levels so the screenshots may not be directly linked to the card(s) in this review. This is because they are all the same reference design from the same production line batch.
The HD6970 overclocked to 950mhz core, any higher would result in instability. Memory speeds reached 1475mhz (5900mhz effective). The quality of this Hynix memory is as good as we have seen.
At these overclocks we see around an 8% performance increase with the Unigine Engine. Temperatures on the HD6970 rose by around another 3-4 C under load.