Provided the rest of the system is up to the task, the only benefit of 2x 680 over 1x 780 is when you export a lot of HD material to MPEG2-DVD with scaling, blending and blurring being helped by the 2 video cards. If that is not the case, a single 780 is the better choice.
If you care a lot about the render speed to output to DVD, go for 2 GTX 770 cards - VERY fast.
If you do not care dramatically about DVD render speed, a single GTX 780 will do everything else very well and not likely bottleneck your very fast PC for anything at all except for outputting from the timeline to DVD format. By comparison, Blu-ray is more CPU intensive and will not be limited at all when you have a single fast GPU.
On another topic, make sure you Samsung SSD (did you mean 740?) is a 730 or a 740 Pro; the 740 model without the "Pro" designation writes too slow.
Thank you for your help..
Yes the SSD’S are not 740 they r 840 pro sys and (840 evo Srch Drv MAYBE) , work Drv’s are WD red's. I think I'm going with 2 ASUS 770 cards... I've read a lot about both ASUS & EVGA cards and found slightly more positive work reliability comments with the ASUS then EVGA. Yet, I’ve owened cards from both manufactures in the past and still due. Both manuf. had issues and performance. The question is which one now has the least issue, while holding their ground in reliably linked with performance and harmony is all that we seek. Ok, I like the red colour feel, ah. If it was only that simple. (Reliability + Performance x Harmony) - Issues / $$$ = Value and Peace? Oh yea, wallet size too.
Thanks for the words of wisdom and your help. We’re all in this together…
Until then… MJB (Blue-Dragon)