GPU Upgrade?

I won $500 from a contest recently, and I'm looking to upgrade my GPU. I could go a little over, but not a lot.  Currently have a Galaxy GTX 670 4GB card, and I'd like something with at least 3GB of VRAM, but that isnt necessarily a deal breaker.  My processor is a 3570K. And finally what should I do with the 670? Sell it? Can I use it for PhysX? Thank you all in advance for your suggestions!

I don't really know the prices in the US, but I think you can get a good 290 or a 780 with that budget.

Personally I would choose the 290 which is cheaper than the 780 afaik and has 4GB of Vram. Preferable a Sapphire 290 Vapor-X, or the shiny XFX 290.

I think the 670 is a really good card. If you're gaming at 1080p, I don't think you're in any rush to upgrade.

If you do want to upgrade, I would suggest the R9 290. Best price performance card. Just ensure you grab a decent cooling unit.

why don't you pick up a second 670 4 gig card and SLI? I have a friend with a similar configuration and his two 670s dominate everything. It should give you better performance than ditching your current 670 and buying a single faster card.

The Sapphire 290 looks friggin' amazing.  I'm only gaming at 1080p, but I like to run ENBs for Fallout, and stuff like that, and the 670 just isn't cutting it. Tried overclocking it, and it crapped itself. Thanks for the suggestions guys! 

Sapphire Vapor-X 290, that's the card I'd recommend

Wow, I handnt even thought of that. Assuming I could get another card (Preferably just like mine) Do you think performance would be comparable to that of the 290 everyone's been suggesting?

I would say yes. If memory serves, the GTX 670 is a pretty decent card on its own,  and two way SLI has been getting improvements with every driver update. Two of them in SLI is comparable to a 780 Ti performance wise. You don't need the second one to be identical, just make sure it has 4 Gigs of memory. 

So yes, it should be comparable to the 290 that everyone is suggesting.

However, you may run into issues playing games that are brand new until they are out for at least a month while Nvidia gets the SLI profile stable, in which case you disable SLI and play off of one card.

This is my recommendation as I am the type of person who is value oriented, and this seems to be the best upgrade path for you.

Okay cool! I'll definitely check that out!

Good choice. The 290 is good for mods.