Have you tried Perforce (Score 2, Informative)

I happen to also work for a game development house, in the IT department. We have been using Sourcesafe 6 for a while now, but have found that it is often corrupting itself, not the kind of behavior that you want in your version control software. Cvs wasn't a good choice for us, being mostly a Windows shop, and Cvs isn't known to always handle certain types of multimedia files well. And there is a certain amount of comfort in having a commercial package that you can get help from[and for those who are about to flame me, I do like cvs, and I am sure there is some way to get support]. Our company has recently started using a program called Perforce for version control. Several of our projects are on it now, and we haven't heard a peep out of them as far as problems go. You can find more information at http://www.perforce.com/ . It might be a better solution that cvs, and it might not be, but it's worth evaluating.