Upgrade Time: 7970 Ghz CrossFire or GTX 780

[Rotfl cyclone]

So I recently decided to beef up the rig a little more and was curious as to what the best route would be. My system as it is now:

ASUS P8Z77-V Deluxe
Intel i7 3770K @ 4.6Ghz
16 GB G-Skill Ripjaws Z 1866
XFX 7970 Ghz Edition
Antec EarthWatts 750watt PSU
Corsair H100i Liquid Cooler
2 x HDD @ 5400 RPM
1 x HDD @ 7200 RPM
1 x Corsair Force III SSD
1 x DVD/DVD-RW Drive

So my question is this : Should my money be spent on upgrading to a second 7970 Ghz or a GTX 780? And if I run two 7970's in CrossFire will I need to upgrade my PSU? Price is somewhat of a factor, I just don't want to spend over about $550. Right now the same 7970 I have in my system is on sale at Amazon for about $350, and I'm alsolooking at the EVGA GTX 780 SuperClocked w/ ACX on sale for $520.

So what do you think? Should I just get a second 7970? 7970 + PSU? Or just go with the 780?

Thank you for any feedback!

 

[mace200200]

I'd crossfire, the 7970 GHz is still an awesome card on it's own, and you'll be fine on your current PSU.

 

[enemy1g]

I'd go the with the GTX 780. Uncertain if AMD has fixed their screen tearing problem with crossfire, but I feel as though you'd get more via the 780.

You could likely still sell the 7970 on ebay (mining is still popular, right?), and make up most of the money to purchase the 780.

 

[mace200200]

Here's a benchmark: http://www.tweaktown.com/tweakipedia/27/amd-radeon-hd-7970-crossfire-benchmarked-at-7860x1440/index.html
the single 780 is a bit faster but not enough to warrant the extra money. Unless you don't really care for the idea of multi card setups (I've never been wild about the idea myself actually) then I'd go with the 780,