Help with next GPU to get !

[Jordan777]

Ok so BF4 is just round the corner and looking to upgrade my 6950, the question is what do I go with next ? Looking to go sli or single card setup so do I go for the following, have £500 to spend ?

2x 7950
2x 7970
290x single card
2x 280x ?

Or just go single card ? Been tempted with 2 7950 at the price there at but looking for some advice as I will be playing arma 3 and bf4. Also specs below

Jord

 

[Jordan777]

Well the problem I am having if I buy 2 7950 or 7970 it's going to be quicker than the new cards surely if got just one single new and card like the 280x ? Not 100% on crossfire so if I am wrong please correct me ? Or is it worth waiting and getting 2x 280x ? Or just 1 290x ( can't afford 2 )