Upgrade to a dual gpu solution or newer single gpu?

Hey guys. My current system is just fine the way it is, but I have worked for a couple of weeks now in the summer and have earned a nice amount that I feel should go into my system.

With that out of the way I am running an i5 3570k, 16gb of corsair ram(@1600mhz) xfx7950, 1 ssd, 1 HDD, 700w bronze modular psu. What I am thinking of doing is a generic upgrade. I LOVE gaming on this pc, it has not let me down in any way. So here is where I am currently at. I am considering getting an identical 7950 and run them in crossfire. Problem is I have never done this haven't heard the best of things with 2 GPUs. My other solution would be to sell the current 7950 and go for something higher up in the food chain like a 780gtx or 7970 or go mental and pick up a 7990. Thing is if I go for crossfire I am worried that 700W psu will not be enough power? and the problem with a single GPU is that I wont have money for a further system upgrade(maybe another SSD for raid 0, or faster ram) 

 

Any ideas? or suggestions? 

If your system has not let you down yet with the games you play, and you just want some headroom for next gen game; I personally would go with a second 7950, as its a beast of a card for the money (had a drop in price recently making it even better value then it was befor), and the crossfire issues have been sorted out. 

Regards your PSU,  AMD specifies a minimum of an 700 Watt with combined +12 Volt continuous current rating of 46 Amps or greater and have at least four 6-pin PCI Express supplementary power connectors. (so you should be fine if you have a good quality PSU?) 

But if money is no object get a 7990. 

700w is plenty enough for two 7950's

700 watts is too much. take a look at the last page of this:

https://teksyndicate.com/forum/other-hardware/power-supply-paradox/144195?page=1

with 2 7970 and a supercharged 8350, I have a max draw of 705watts.

But this is from the wall. not the PSU. Do the efficiency calculation on it, and it will never be higher that 600 watts. 600 watts for hardware that draws much more that yours will do. 700W should be fine.

Just a bit worried about crossfire :P heard it doesnt play nice with some games. I suppose a OCZ bronze 750 W psu should be alright (just realized it was 750:P). I am guessing going for a raid zero + a second GPU would improve my overal performance greatly rather than just going for a single 7990