My current card is a GTX 260 Core 216 1792MB.As I am on budget and want dx 11 I want to buy a GTX 460 SE and go SLI in future .Now is the SE edition a bit more powerful than my 260.I know its not a huge upgrade but I really want dx 11 but only if the SE is better than my 260.If they are the same I may buy another 260 and go SLI.So is the SE more powerful than the GTX 260?I am also considering gtx 460 768mb so please advise me on which card I should buy?
Don't go for the SE edition if possible, it's just a crippled version of the 460. Try and go for the full fat edition, you'll see a noticeable performance increase as well as DX11 capability.
Also, go for the 1GB versions of the 460, it will benefit from the extra memory.
PS, is your RAM 3 x 2GB sticks or 2 x 3GB sticks, if it's the former, i suggest you remove one of the sticks to bring it down to 2 x 2GB sticks so you have dual channel memory performance, this will help your PC a little bit.
Or he can run 1x4gb and 1x2gb. I think that will work in dual channel mode without loosing the performance in single channel mode. Correct me if i am wrong on this one because i do not know what impact that has on performance versus your explication above.