dual video cards

Hi, a have a 8600gts 256mb which was running my 22" widescreen and my 19". i bought a while back a 8600gt 512mb (kinda messed up with that one as i thought it was the one i already had, so sli is out). Anyways i wanted to hook up the dual cards and according to the reading i have done on the net it is apparently possible to run 2 different monitors of the different cards (not sli). The 2 different cards show up in the system but the nvidea control panel wont detect the monitor plugged into the second card. It will be a few of months before i will be able to upgrade my system. So is this possible and will i see a preformance increase or am i better off just keeping with the 8600gts running both).
I usually run between 1 and 5 instances of wow with the 4 slaves running on the 19".
Any help would be greatly appreciated, thanks :)

Mibane

I was runing 2 monitors 1 card It ran great then i switched to 3 monitors and 2 cards Ran really crappy i ended up just going back to 1 card 2 screens and ran a 3rd comp for 3 monitor .

If you don't know how to set it up, multiple cards can HURT your performance (as Budkin apparently found out). See [Other] Windows 7 and dual screen

My recommendation is to stick with 1 card with up to 2 monitors

thanks. after reading the link i think i'll settle with the one card until i can upgrade to my i7 system.