Also thoughts about 660Ti (ASUS normal or OC) vs 670? Is the extra £100 and extra memory bus from 660Ti to 670 worth it?
More aboutasus 660ti normal edition
Extra 52MHz is not worth it when you want to try to overclock yourself. But, the OC card is guaranteed to run at that speed. Stock cards usually can easily go past that OC 'd clock.
I don't think an extra £100 is worth it compared to the 670.
If you have the money, go for the 670. Not only does it have lower memory bandwidth, but it also has reduced ROP count which further decreases performance.
Just get the cheaper one and overclock it yourself. If it was the Asus TOP version, I would say it's worth it for a higher binned chip and much higher factory overclock, but it's just a minor OC on this one.