So I was originally going to get a 780 lightning but then my friend offered to sell me his gtx 690 for $500 (upgrading to a 780 ti). I game on a 2560x1440 monitor. I would have loved to get an r9 290 but it looks like the after market cards aren't coming until January.
I've never had a multi-gpu configuration before. Essentially:
2gb with 256 bit bus vs 3gb with 384 bit bus for 1440p
SLi vs single gpu frame times
600 series technologies vs 700 series (i.e. gpu boost 2.0)
While multi-card frame latency is (generally) higher than single, the 690 doesn't go above 3ms frame latency in any of the games tested, which is hardly noticeable for me (I'm currently running a pair of slightly overclocked 670's at similar frame latencies)
I'm surprised he's selling the 690...it's stronger than the 780ti and Nvidia's frame pacing is so good, multiple GPU latency is visually indistinguishable from a single card.
that isn't the complete answer to my question. What about 2gb with 256 bit bus vs 3gb with 384 bit bus for 1440p
It should have been. I guess I didn't mention I'm using a 2560x1440 potalion with those 2 670's, and the overlord OC circuit board in the monitor, so it's running at 108hz as well (it's in my profile). I like to stay at 90 fps minimum with most eye candy on.