Which one Dual 280x or gtx 780 or asus 7990
I would go gtx 780 because AMD has a history of bad frame latency with crossfire. Also a single gpu is more compatible overall and will usually give you less headaches. And those AMD cards will sound like a vacuum cleaner in your computer :)
since PS4 and XBONE use AMD hardware i would chose AMD but not the HD7990 because it is kind of "LAST YEAR"... perhaps 2 x R9 280x (frame time problems for directX 10 and above are fixed) or maybe one R9 290X with custom cooling made by ASUS or other vendor... or a closed loop liquid cooling.
but hey... if you have the cash and dont mind spending it... go with dual gtx780TI :)
780ti.
I'm Going for the 780 range as well as my mate has two 7990 and crossfired well sucks he is also going for the 780 mainly as its two bays now
Depends on your display?
A single 1080p monitor would only require a single 280x
How about one of the 290's that can be BIOS flashed to a 290x? $550 dollar card for $400, if you could spend a bit more you could have a 290x Crossfire setup for $800 clams!
Why not look at a 290 or 290x
Dual 280x > GTX 780 > 290 > 290x at 1080p
At 1440p its real a hard decision.
You will get slightly better performance running a single 290, While the 280x crossfire will perform the best you will have issues with Vram. Same issue with the 780.
The upside to the 280x crossfire is best performance however with frame latency issues that have been improved on but not resolved, you have to consider that. Not to mention not all games support dual GPU's.
The 780 has the best performance to temp and power draw ratio. Its the same price as the 290x now but with 3gb's of ram, you will see issues with some games. I am in a pickle where I want a 1440p screen but skyrim with all my mods fill my vram almost completely in some select areas. If I got a 1440p screen, I would ned a 4gb card or would have to reduce the resolution of my textures in some games.
The 290X I would not touch. not at all. Its younger brother the 290 will out perform it when both are overclocked. It overheats and it only has 2 things going for it that its younger brother shares. 4gb's of ram and better performance scaling at higher resolutions.
The 290 has great potential. I have seen a few posts on other forms where someone has a 290 with an aftermarket cooler and it was blisteringly fast. However it shares the same heat characteristics as its big brother and until stock aftermarket coolers come out. Its a hard choice. At 1080p, the crossfire 280x's or the 780 will blow it away. 1440p, Are you willing to take the heat issues of a 290?
The 7990 is essentially underclocked 7970's which have an even lower clock than the 280x's. I wouldn't buy if you are considering a 280x crossfire unless you only have 1 or 2 slots in your computer and need more.
Ill throw in the titan here. Now the titan is an oldish card. It does not out perform a GTX 780 and it does not have a custom cooler officially but you can buy an ACX cooler from EVGA and "Modify" you GTX titan. This would also require a modified bios to allow for a higher TPU limit as the Titan is restricted by it. However it is the only card I could really say has the potential for higher than full HD resolutions other than the 290 once they sort out the cooler. Sure its very expensive but that 6gb's of ram would be amazing for greater than full HD gaming.
The final option is wait for the 800 series. Their going to have to bring out atleast 4gb cards. 6gb's I hope and then you will have enough Vram for new resolutions but if you only want 1080p gaming. its completly useless.
Final comments. Want higher than 1080p? Wait a year. If you cant well there are ups and downs for all the different cards available. none of them are good enough in their current form to fill this slot at this moment. Some with tinkering will but your looking at 800-1200$
Only want 1080p? I would go with a GTX 780/ti. Or a 280X crossfire. Depends on if you want to deal with the hassle of 2 cards or not.
Honestly I would recomend to everyone to wait for the 800 series if you can. Unless you have the money to blow, These current series just dont have the Vram for what we really need for high end gaming or if they do they are very expensive and or have terrible cooling.
I would say to everyone to at least wait for the 290 or 290x with an aftermarket cooler.