2 7870s vs newer single cards

I upgrading my pc soon so I can run 3 monitors and would like some advice on what to do with my GPU. I currently have a XFX 7870 Core addition. And I dont know if I want to get a another 7870 for crossfire, or get a newer card (or 2 newer cards.). My motherboard supports both Crossfire and SLI. I am open to Nvidia cards, but I don't want to spend more than $500 per card.

I also plan to Water cool and overclock both my CPU and My GPU. so while im hera I may as well ask if my PSU will be able to handle all that. Ill include my specs below.

CPU: AMD 8320 MotherBoard: Asus M5A99X Evo R2.0 PSU; XFX Pro Series 750 Watt

Thanks in advance for the advice.

You've got a nice system. I prefer a stronger, newer, single card. It's less problematic.

I'd recommend an R9 290. Should handle most games really well. Those top-tier R9 cards are geared to push a lot of pixels.

Whether or not it will meet your expectations depends the games you wish to play, and your preferred quality settings. I would assume that it could handle BF4 on ultra textures. You might have to reduce some of the AA and other settings.

http://hexus.net/tech/reviews/graphics/63953-sapphire-radeon-r9-290-tri-x/

my current card,

the prices are a lot saner now so I can recommend one.

I would go with one single card. The 7870s seem to be a big pain in the ass when it comes to CrossFire. They were for me and a few other people. 

Thanks guys. I think I'm looking at a single card now. I  wasn't aware crossfire was problematic for the 7870. Mines never given me any problems. So thanks for bringing that up. 

I didn't think to post the resolution I'm using. I using a 1920X1080 monitor and I want to get two more at the same resolution. So I think that would be 5760X1080.

And about the R9 290, would 750 watts be enough to power one of those, plus a water cooling loop, and still have enough power left to overclock?

Thanks again for the help!

Both crossfire and SLI are good solutions, but they are not perfect. Not all games support dual card configurations.

The R9 290 is geared towards emerging 4k monitors, and high resolution gaming in general. I'd confidentally say it is one of the best considerations for your budget.

You could power your system, with an R9 290, on 500W. 750W is going to give you lots of headroom.

No problem. 

Yeah the 7870/270(x)s are great cards especially for the money but yes it appears that some cards work better together than others together. The GTX 760 seems to do very well in SLI with good scaling and game compatibility.

The 7870 though doesn't for some reason. I ran two and they were terrible. Some games wouldn't work at all and others were slower. Some were amazing but it was just way too much of a headache. I know Logan mentioned similar issues when he reviewed some 7870s a while back and it seems to be a fairly commin issue. 

Alright so Eyefinity at that resolution. An R9 290 would be a good choice as would be a GTX 780. Just be sure that if you go with the 290 you get one with a good aftermarket cooler or put your own water cooler on it. The reference 290s are furnaces that will throttle hardcore under load and sound like vacuum cleaners. The non reference ones or a reference cars with something like the NZXT G10 and a closed loop cooler are fine though and a great bang for the buck now that prices are seeming to go back to normal. 

750W will be plenty to power that system. I mean it depends on your CPU as well but in my main rig with a highly OCed 8350, a 780, a Kraken X60, two SSDs and one mechanical drive, and a butt load of RAM I'm only pulling 530W. 

Computers don't draw as much juice as people think. 750W would be plenty so long as it is actually that rating. Make sure the PSU is from a reputable manufacturer and can actually put out the power it says it can.