As high? I doubt it simply because the card really isnt quite as optimized. What you're really buying with a 295 is a pair of beefed up 260s that fit a single slot. This allows you to save space, do greater sli configs (if you can really shell out that much cash for 3 of these), and not be limited to sli enabled motherboards for sli performance. The downside is that you really need to cut corners when shoving two cards into one slot, as you may imagine. Even if you don't get quite as high an OC out of it, your total performance (on any multi threaded game, which is to say any game you wont already be getting 200+ fps on) will be higher than a 280 or 260. The real question is do you want to deal with two 260/280s to get slightly better performance per dollar or save space and allow for greater scalability with a 295.
Oh and yes to conclude my rant and get back on topic - I doubt the OC will get quite as high but the difference should prove to be negligible compared to the differences of the cards themselves.
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