Has anybody tried HyperSLI? The tl;dr: It's a modded driver which allows SLI with different Nvidia cards (i.e. a GTX 570 and a GTX 670). If anybody has, how'd it work out for ya? I'm considering trying it out, since my 570 is just being used as a dedicated PhysX card right now.
I don't understand how they get around cards not being capable of the same functionality. Surely if you put in a 2xx series with a 5xx you wouldn't be able to run DX11 effects properly? 4xx and 5xx are the same-ish cores, while 6xx and 7xx are as well. Have you seen anyone try 600 and 500 series together? I'll have a spare 570 once the 780 gets in...but I'd rather continue avoiding SLi issues by sticking with one card.
I've been reading through the thread, and it seems like a lot of hitting and missing. Either your combo works, or it doesn't, so either there's still some work to do for him before it works somewhat reliably, or it just won't work reliably at all, ever. I'll probably stick to a single-card configuration as well (with a PhysX card on the side), for now. Also, GIVE ME YOUR 780! D: I hate being just a student with no money at all for all these neat new gadgets :<
As far as I know, in order to not have the computer explode (overstatement) the faster card would have to downclock to the lower speed or maybe the timing difference would increase micro-stutter. Interesting thought, surprised it hasn't got more attention being from 2012.
SLI is designed to be symmetrical, which is why it needs the same model of cards to work (officially anyway). So I doubt this hack will ever work perfectly unless Nvidia changes the way SLI is designed. This is one of the reasons Nvidia has much smoother multi card performance than AMD, because AMD's design is asymmetrical in the first place.