wss_003 :
One card with 6gigs i ment
Crossfire and SLI will not give you twice the ram, the memory on the card does not add-up
because both cards need to hold the entire information in order to process the frames, so the content
on the cards is mirrored...so if you put 2 card with 3gb each you still just get 3gb usable VRAM...
That is the reason why they came with a 6gb titan...
at the end of the day i thin you would need 2x titans to be happy on the nvidia side
but it does not fit in your budget of 1500$, or you jump the fence and go AMD they have
4gb. cards for a good price you could fit 2x r9 290 in your budget but you need to fit
somthing to water cool them...also corssfire does wierd things and is not supported well
in many games so you might end up playing some titles on only 1 card...wich sucks...
so if i where you i would get eiter 2x GTX 780 and maybe lower the textures settings a bit
if some games uses more than 3gb, or just get a 780ti and save some money and reduce the
graphics settings if needed to stay at around 60fps...the choice is yours.