While both the cards we've managed to grab for this initial review are pre-overclocked, there's always extra performance to be eked from such cards, so we set about pushing them that little bit further.
The MSI Power Edition, equipped with the excellent MSI afterburner overclocking tool, clearly had some etxra in the tank, especially with its stock memory frequncy of 1.5GHz (6GHz effective). Some stress testing later we settled on a base clock of 1,100MHz, an 80MHz increase over it's factory boost,with the card boosting to a peak of 1,322MHz in Unigine's heaven benchmark. We also increased the memory up to 6.7GHZ, a tidy 11 per cent increase and resulting in a memory bandwidth of 160GB/sec.
We managed even higher clock speeds when overclocking the Zotac amp! Edition, hitting a base clock of 1,133MHz and a memory frequency of 6.7GHz. However, despite a higher base clock, the amp! Editon wasn't as happy to boost to the top of its boost curve and capped an MSI matching 1,322MHz, resulting in both cards performing near-identically in our overclocked benchmarks.
Interestingly the GTX 660 Ti 2GB's limited memory bandwidth means that, even with a hefty overclock, it still can't match the performance of a stock GTX 670 2GB. This isn't the case when comparing an overclocked GTX 670 2GB and stock GTX 680 2GB, which are roughly equal, so while the GTX 660 Ti 2GB isn't too far off the GTX 670 2GB, there shouldn't be too much buyer's remorse amongst 670 2GB owners.
Overclocking - Battlefield 3
2,560 x 1,600, 4xAA, ultra detail settings, DirectX 11