It beats the 7950GX2 in EVERY test I've seen on the internet. By quite a significant margin too. If you can show me a test where its slower than the 7950GX2, i'd like to see it. Although it wouldn't really be able to convince me to buy a GX2 anyway really. The 8800GTS is cheaper.. and from all the reviews I've seen about it, its miles faster.
Where are you buying from?
And can i just confirm, you saw an 8800GTX for £293? If so, please tell me where this is! Cheapest GTX on Scan is £379.88 not including VAT. Cheapest GTS is £289.88 (not inc. Vat). And thats a really cheap brand. For the ASUS version its £304.49