I just recently purchased 2 xfx double d 6870s for $170 each [rebates are to still be applied if i keep]. They are still in shipment and should be arriving at my front door tomorrow. After much reading though, i have still been in debate about this. despite the extra 1GB on the 7970 [which might be more helpful since its only a single card as oppose to two cards with 1GB each], i've been readin' around that 2 6870s CF almost equivalent to a single 7970. whether true or not would help, the cost of a single 7970 averages to around $480, especially if i go for the sapphire OC version as oppose to two of these cards that would equal to less than $300.
according to this chart and i go true with the '3 tiers' above my current card (5870 1gb vapor-x oc), that would put me at the 7970 anyways. i also read that my current card out performs a single 6870, and that two 5870s cf would actually do worse than a 6870 cf.
should i return the cards while i can, and just spend an additional $200 on a 7970? i was also debating on if i should just wait it out and see if amd will release the dual 7990 instead [despite the obvious enormous price jump]. at the same time i won't have to worry about another card for many years to come [assuming it performs well].
from what i've seen games have gotten more support with nvidia physx. the witcher 2 has absolutely no support for triple display through amd as oppose to supporting not only 3d from nvidia but also vision surround.
with that being, i could actually go back in time and experience RE5, even though i don't have 3D capable monitors. still a tough debate. i've always wanted to experience a dual card set up, and one thing i don't really care about what amd has done with the 6000/7000 series is the abandoning of the display-port in favor of mini-display port. not that big if an issue i guess, if i buy a doggle for the cable, but still annoying, considering that the gtx 670/680 [not sure on 690] both have original display port output.
Nothing wrong with nvidia, and as it stands their drivers are better than AMD at the moment.
I see people write this all the time, but what specifically is wrong with AMD's drivers?
OP, Crossfire 6870s are probably a little slower than a single 7970. 6870 ~= 5850. 2x5850 ~= 5970. 6xxx series do scale a little better in crossfire than 5xxx series. 2x6870 is probably somewhere between gtx580 and hd7970.
From a value standpoint, you're comparing gaining a slight performance advantage for +$150. If you're willing to spend $500, I say go with 2x7850 instead. Power usage for 2x7850, 1x7970, and 2x6870 is going to be ~300W for all three setups, with performance in that order.
yeah, i forgot the about the micro-stuttering. maybe i am better off with just one card then since these cards i ordered only have 1gb of vram each and probably won't benefit any at all on high end games like bf3 or crysis 2.
edit: also i dont really plan to play online. i'm more of a single player approach, especially for rpgs.
I've had ZERO issues with micro-stuttering. Logged a couple hundred hours in BF3, across different driver releases. Personally, I think it's less a problem than the media makes it out to be.
The thing that does hold back the XFire setup is the lack of sufficient VRAM when in EyeFinity. I can't play BF3 on very high settings if I play in that, over a single display. Unless you plan to run more than one monitor, you should be fine with the 6870s.
Micro-stuttering is an issue if you have low fps. If your fps is +60 on a 60hz monitor, you shouldn't (or won't) see any micro-stutter. A choppy framerate is a choppy framerate regardless of if you have one or two cards. With two cards, you get micro-stutter because of the choppy framerate combined with your cards not outputting frames in the exact same intervals. That doesn't mean single card setups can't have choppy framerates. You still need to adjust your game settings according to your hardware. People assume they can murder every game on ultra with their multi-card setups, then scream about micro-stutter. Lower your settings to within your hardware's capability and you'll find it goes away.
On my setup, I don't see it until <50 fps. In practical terms, that means I run BF3 on medium w/ 2xMSAA at 1920x1200 to keep +60 MINIMUM fps (mainly on the Karkand maps). 2x5850 is supposed to be ~= to gtx580, and I do see people say they run omgwtf ultra settings in BF3, but they're not getting +60 minimum fps. I guarantee they're getting <30 fps frame dips during explosions on Karkand maps. Yes, they won't have micro-stutter, but it's still not a completely smooth experience. Most games I can run at ultra settings with no micro-stutter (e.g. SWTOR, BF:BC2), a couple I run at high + AA (e.g. Metro 2033).
2x7850 should have no problems with ultra settings or micro-stutter in any current games. That's still my recommendation for $500.