I've started to notice that my single Radeon Hd 6950 2Gb isn't enough for games anymore (I play at 1920x1080 resolution) so I thought about getting another 6950 and running them in crossfire. Would that be enough gpu power to last me for at least a year and half or something along those lines OR should I just buy the more costly Radeon Hd 7970. I want to get me something that can also run upcoming games somewhat smoothly like Crysis 3, Half-Life 3, the new Tomb Raider etc. Any advice appreciated.
-Amd FX-8350 @ 4.6Ghz/cpu-nb 2600mhz
-Asus SABERTOOTH 990FX R2.0
-Noctua NH-D14 cpu cooler
-G.SKILL Ripjaws Z Series 2400Mhz 8GB (2x4Gb)
-PSU Corsair TX850W V2 Enthusiast Series
-Corsair Force 3 120Gb SSD SATA III + Seagate Barracuda 1 TB 64 MB 7200 RPM 3.5" SATA III
-Chassis Corsair Graphite 600T Special Edition White
In general ... 1 more powerful card > 2 less powerful cards.
Crossfire leads to problems such as micro-stuttering and uses more power and produces more heat. The 7970 will use less power, it will produce less heat, and it will (most likely) play most games more smoothly than a crossfire setup will.
Given you list of games, I'd go with the 7950 or 7970.
The 6950 2gb is getting pretty hard to find at a reasonable price, even used. Find one and do the price comparision. You might be better off selling your current card and buying the 7970, especially if you have the reference version
Well I want play with ultra settings at 1920x1080 resolution so single 6950 doesn't really give me the smoothest possible gameplay, especially with newer games or upcoming games. I just want the games to look as good as they can and also run as smoothly as they can.