Good versions of the Radeon HD 6950 2GB?

Dude avoid CF or SLI at all costs unless you like to game next to a turbine jet and sweat like a pig from a heat CF/SLI will produce. How do I know? Because I've done it  
Sold both cards and got 7950(~$300). I'd recommend the same or go for GTX670(~$400).

Good luck

I agree with maxinexus, sell your card and go with the fastest single card you can afford. Crossfire (and SLI) just have too many issues.

A GTX 670 will probably get bottlenecked, so would the 680 (was planning for that), since I've got a phenom x6, with a quiet mild 4ghz overclock. I was going for the 6950 CF just to step up performance for the price, I'm on a budget right now, and I've maximum got about 200-220 euros. My friend runs CF and SLI on both of his rigs and he's never had problems, what's so bad about it?

for a crossfire configuration, personally, i would either get one or both cards that output the heat out the back. traditionally this kind of cooling set up doesnt cool as well (as cards designed to just blow the air into the case) however when you have 2 cards sandwiched together i think its a bad idea to have the top card blowing onto the bottom card. best if the top card puts heat out the back.

I can space them out, their going to have about a handspace between them, I've already got a dual fan card that blows air into the case, but gets exhausted from the side and the card gets fresh air from the front of the case, (35-40c idle, 68c max on full load) which works well, so you recommend a reference card or another one?

A GTX 670 wouldn't be as CPU-bottle-necked as two Radeon 6950s. They're similarly performing, but Crossfire has a considerable CPU overhead.

I partially disagree with the others here, CF/SLI aren't so bad (especially with cards that have VLIW4, GCN, or Kepler GPUs), but it's not ideal for your situation. Selling your 6950, getting a 7950, and overclocking it is probably your best solution.

Watercool them.

water cooling is expensive. better off just getting a new single video card

Its really not that expensive anymore and the results it can provide are well worth it.

I have an XFX. I cross-fired with a sapphire........ same XFX wasn't available at the time. Alone they ran fine. together they had their ups and downs, ( had them set at stock speeds ) something I never experienced with sli or xfire before. they now run in separate machines fine from one another.

tough call to say go ahead and xfire from my standpoint. they both run games at 1920x1200 without any flaws, hiccups or reduced settings.

I would hold off spending the money until I could make a substantial single card upgrade. Hard to do because I like buying new cards and do all the time......... it's a sickness.... LOL

Two water cooled 6950 2GBs really aren't going to beat a well-overclocked 7950 with a good non-reference cooler, but they will be a lot more expensive than it. Water cooling might not be expensive, but it would be a great example of paying more for less compared to OP selling the current 6950 and buying a 7950.

it IS that expensive for videocards, heatsinks for videocards are an upwards of 100 dollars each

I get your point honestly I do. If you want to have the best performance for the least ammout of money just stay with one 6950, at this time you really dont seem to need more unless you are going for bragging rights.

True to that...I upgraded just for heck of it...don't really need more power since I play games once in a while but when I play I want top resolution and all eye candies on...CF is faster but I drift away from watercooling because of the new hardwood floors   I did get some leaks from time to time.

Lol, true. Watercooling is nice but honestly it takes allot of time and effort to make sure everything is in 100% working condition. Honestly I do not use my watercooling rig for gaming I use it for F@H 24/7 operation on high grade tech causes allot of heat this was my only way to cut down on it.