Ladies please, thanks for your input, but don't turn this into another amd vs nvidia fan battle.
I know the 7950 is a better card, but id want something like the msi pe version, not just the cheapest. I have considered a 7950 in terms of price and performance, but if I spend almost £300 it would be more beneficial to just buy a 7970.
I am open to suggestion though, I will probably end up going for the 7950, just want to see if anyone has experience with the 660ti compared to a 6950>70 or a 7870.
I went from a 6950 to the 7870, even at stock the difference is already fairly significant, i can't remember by what or how many FPS but it was very noticeable.
Overclocking the 7870 overclocks much higher and scales higher.
all in all it was a huge step up. the 7950 while only 10% faster than my 7870 at stock, it has much higher overclocking headroom because it starts out with a much lower base clock, clock for clock the 7950 eats the 7870 alive.
I bought my 7870 at the time when the 7950 was around £300, i did not think it was worth that. now at £240 for an MSI 7950 TF III, it's by far the best GPU you will get for that. it's better bang for £ than the 7870 and certainly the GTX 660ti