Gaming GPU for 1440p Qnix

[AllstarButt]

I'm looking for a GPU to run games on a 1440p screen for my upcoming build. Budget is around $800. The options I'm currently looking at (prices are canadian):

780ti EVGA ACX $820 (SLI would take more time)

290x Sapphire Tri X $631 (eventual crossfire)

290x Gigabyte Windforce $540 (crossfire sooner)

290 Sapphire Tri X $421 x2 = $850 (immediate crossfire)

some other combination I haven't thought of.

must be compatible with:

4690K
Air 540
Sabertooth Z97 (can swap for different Z97 if suggested)
1000w PSU
Qnix QX2710

Will be playing games like the Witcher 3, BF4 and Heavily Modded Skyrim.

 

[Bossnutz]

I'd like to know the answicjer to that ? as well... Also which GPU for a Yamakasi Sparta 301 1600p??? Im leaning toward a R9 290, any suggestions?