Well firstly, have you bothered to try
without patching? You didn't seem to test it pre-patch and as far as i can remember i never patched Necrovision personally and didn't notice any game ending bugs, so is the patching even necessary?
A quick google search has led me to believe that this game may not actually support multi-GPU. I'd be happy to be proven wrong, but this does seem quite common with games that aren't as well known to the general public, certain features such as multi-gpu support or multiple monitors may not be supported, but there is usually a fix or two out there.
Reading one forum, people suggested that you may need a "sli patch" to allow the game to function properly.
The forum -
http://www.nvnews.net/vbulletin/show...=129324&page=2
The link they gave -
http://www.evga.com/articles/00463/
Infact, had you looked on our very own forums here, you would of noticed the exact same questions being asked and the same answers being given.
http://forum.1cpublishing.eu/showthread.php?t=6186
However i feel i must point out that your comment "if i have to remove 1 of my vid cards to play this game it doesn't make sense to keep the game" is a bit extreme and quite inaccurate.
Unless you are one of those elitist types who simply
must play with a huge # of FPS you can run the game perfectly fine with just one card.
I've only got the one and the game runs as smooth as a greased up rat on ice...I think you should just try disabling one of your cards and enjoy the game for what it is, which, is much better than Painkiller (or the poorly made expansions) ever could be...PK was dull and repetitive even after the first level.