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#11
Yes, I think that a GTX 650 will be a waste for your current CPU, but if you are going to a new motherboard and new CPU, it will be nice.
If you want some extra performance than the GTX 650/HD 7770, I found these cards on Newegg.com:
Newegg.com - PNY VCGGTX650T1XPB GeForce GTX 650 Ti 1GB 128-bit GDDR5 PCI Express 3.0 x16 Video Card
Newegg.com - EVGA 01G-P4-3650-KR GeForce GTX 650 Ti 1GB 128-bit GDDR5 PCI Express 3.0 x16 HDCP Ready Video Card
(Assassin's Creed 3 game included!)
It's the GTX 650 Ti 1GB. It will be faster than the other 2 cards.
But keep in mind that 1GB video memory is not really much for today titles, so a 2GB solution should be better.
as nostaw5 said, if you can wait to keep the GTX 670, it will be the best choice if you are going to a new CPU and motherboard (you need at least a quad core CPU to use it).
Returning to HD 7770 1GB vs GTX 650 2GB... Well, the difference is minimal, but the GTX 650 has got the 2 GB VRAM...
And keep in mind that a slower Nvidia card, compared to a 10-15% faster Ati Card (in this case, the HD 7770), will have the same performance level in games since Nvidia uses better drivers than Ati ones; they're also updated more often and they contains costant improvements for games.
And also, the Nvidia GPU will render PhysX too.
Since you aren't going to use multi-GPU, in my opinion you should go for the GTX 650, because of the 2GB VRAM, better drivers, better support for games, PhysX support,...
(the HD 7770 should be a good card too :) )