so atm i have an asus direct cu 2 top gtx 560 @ 925mhz.
Its a great card, but ive read, that when i wanna use multi monitors (im planning to get 2x 23" or 3x 23" soon) then AMD is the best for that.
So, what is the equivalent (performance wise) to my card and should i crossfire it ? I mean, crossfire is almost double the performance (so-so), but it also causes microstuttering etc.
What are your opinions on this matter ? Oh and also, will my fx-8120 bottleneck the xfire setup ?
If you get another GTX 560 to run in SLI, you can run three monitors. Two off one card and one off the other. If your board doesn't support SLI and you really want to go crossfire then on the ATI side a 6870 would be the performance equivalent of your GTX 560 with the Radeon 7850 being a step above that. Considering you have a 600W PSU you could crossfire two 6870s, but I would rather spend a little more to go with the more miserly 7850s.
I should say though that I think you're better off getting a single more powerful card now (like a 7950) and add another one latter in CF when you need it. Of course, your CPU might prove to be the limiting factor in some games before you need that next card even if you're running three monitors.
i have an 990fxa-ud3 mobo so it supports sli and xfire.
Altho i think my gpu might be a bit flaunty.
It takes lots of time to render some stuff in games, some stuff are really blurry when looked from far distances and then they get better when you get really really close. (textures etc.)
If you plan on going 3 monitors then skip the 7850 and as a minimum go with a 7950 if not a 7970. For single monitor performance a 7850 is fine, but when you go up to EyeFinity resolutions the extra gig of VRam that the 7950/7970 have helps (I've already seen games at EyeFinity resolution go past 2 gigs of Vram useage), and just the extra power of the cards is needed. Even with a 7950/7970 you wouldnt have enough power to max games at EyeFinity resolutions but they'll get you close. If you are considering crossfire, I'd still go with a 7950 and crossfire it later compared to cross firing 2 7850's now and only having 2 gigs of ram.
Your 8120 will be fine and shouldnt bottle neck as long as you overclock it.