Don't know for sure because 770 is out yet, but it is basically a slightly (very slightly) better GTX 680. So the performance difference would probably be the same as 670 vs 680, which isn't a whole lot.
There is very little benchmark info on the GTX 770 and the pricing has not been released but its is supposedly faster than the GTX 680. For more infor you'll have to wait till the release as only the GTX 780 is currently out.
From what I hear, the GTX 770 is going to be a rebranded GTX 680. Obviously there will be performance increases across the board, but don't expect the price to be anywhere near the price of a GTX 670, not just yet anyways. Honestly I'd say try to get yourself a used GTX 670 which can be found for about $300-$350 for the 2GB version. Or you can get yourself a used GTX 680 for about another $50 more.
i want to buy new only so should i go with 670 for next gen games for 60fps on ultra 1080p
You should be fine with a GTX 670 for 1080p 60fps for most games, but don't expect 60fps constantly. There will obviously be some demanding games that won't let you get full 60fps(Crysis 3 for example). But all in all you should be fine with a GTX 670. If you want to wait then I believe May 30 is the release of the GTX 770. You can wait and see how that performs and if its near your budget(probably won't be).
what is ur thought abt pricing would 770 cost very more ot bit more thn 670?
I can not say for sure, but I would expect it to be around the price of a new GTX 680. But don't hold me to that. just wait till the end of the month when the card releases to make your decision. If you can't wait that long then you should be perfectly fine with a GTX 670.
Couldn't hurt to wait till the end of the week and see what happens, who knows maybe with the release of the GTX 670 there could be a price drop with the previous line(don't hold me to this as well). If you really need the card now then you should be perfectly fine with a GTX 670.
i will wait thnx and plz tell me the performance dffrnce btn wd black and barracuda thnx
Performance wise both drives are great. They both run at 7,200rpm and have 64mb cache. I would HIGHLY suggest you get WD Black because it comes with a 5 year warranty and it is probably the one of the best Hard drives in the market now. Seagate was a great company about 5-7 years ago, but now their quality has dropped a lot. Your better off with Western Digital, it's what I use and it hasn't failed me since.