670 SLI Vs 7970 3gb CF Vs 7970 6gb Cf plz respond

All three of those solutions are going to perform exceptionally well. If you notice frame latency at all, go with the 670s. Otherwise, go with normal 7970s - I suggest Vapor X's.

There' no need for the Toxic editions, as 3GB of vram is plenty for three monitors; the 590 only had half that per chip, and performs wonderfully.

Crossfire is not recommended at this time. Crossfire on an Eyefinity setup is even less recommended. The GTX 670's in SLI are really the best option right now for smooth relatively stutter free gaming on multiple monitors. The 4GB versions would be ideal.


Quote:
"Where AMD has definite issues is with HD 7970s in CrossFire, and our Frame Rating testing is bringing that to light in a startling fashion. In half of our tested games, the pair of Radeon HD 7970s in CrossFire showed no appreciable measured or observed increase in performance compared to a single HD 7970. I cannot overstate that point more precisely: our results showed that in Battlefield 3, Crysis 3 and Sleeping Dogs, adding in another $400+ Radeon HD 7970 did nothing to improve your gaming experience, and in some cases made it worse by introducing frame time variances that lead to stutter."

"The second major concern for AMD CrossFire users occurs when you enable triple-monitor configurations with Eyefinity. In every single game we tested, even Skyrim, DiRT3 and Far Cry 3 that didn’t show major runt issues on single monitor resolutions, just about every other frame of the game was being dropped. Just like the runt frame issue we mentioned above, the Eyefinity drop problem basically means you are running your 5760x1080 configuration at the performance level of a single HD 7970 even though you have invested twice the money AND that other performance software (in-game tests, FRAPS) are telling you differently. The results are so bad in fact from the recorded video that the FCAT Perl scripts aren’t quite able to decipher them because it thinks it is a poor capture; we can assure you that is not the case."
http://www.pcper.com/reviews/Graphics-Cards/Frame-Rating-Dissected-Full-Details-Capture-based-Graphics-Performance-Tes-12


The latest reviews of the 7990 have exposed some serious flaws that are 100% valid for 7970's in Crossfire as well. Here's a sample reading selection.
http://www.pcper.com/reviews/Graphics-Cards/Frame-Rating-Dissected-Full-Details-Capture-based-Graphics-Performance-Test-3
http://techreport.com/review/24703/amd-radeon-hd-7990-graphics-card-reviewed/10
http://www.hardocp.com/article/2013/04/22/nvidia_geforce_gtx_titan_3way_sli_review/10#.UX7PdBPn-Uk
http://www.hardocp.com/article/2013/04/24/amd_radeon_hd_7990_video_card_review/9#.UX7P9RPn-Uk
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/60843-amd-hd-7990-review-malta-arrives-13.html
http://www.techpowerup.com/reviews/AMD/HD_7990/31.html
http://www.tomshardware.com/reviews/radeon-hd-7990-review-benchmark,3486-13.html

For 3 monitor builds, I'm using these:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814121659
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125449

I was never comfy with CF when the possibility existed of a potential 3rd card later on ..... but with all the bad press of late, it now confirms what many of us were used to seeing but couldn't quantify.

http://www.anandtech.com/show/6857/amd-stuttering-issues-driver-roadmap-fraps/6
http://www.tomshardware.com/reviews/graphics-card-benchmarking-frame-rate,3466.html
http://www.pcper.com/reviews/Graphics-Cards/Frame-Rating-Part-3-First-Results-New-GPU-Performance-Tools?page=2#comments