Whenever I start a game or after I load one, sins will hang anywhere from a second or two to ten or so seconds.  It will do this repeatedly (a couple seconds to a minute between each hang) for several minutes into the game.  In between hangs, it runs just fine (it's on max detail and runs smooth as silk inbetween the hangs).  The hangs usually occur when I'm zooming in on ships or planets, so it seems like it's a problem with the game loading textures, but it also happens if I'm moving around the galaxy view or a gravity well.  I've also noticed the same problem in the main menu.  The problem usually goes away after about five minutes of play, but sometimes it lasts much longer. However, It's never actually resulted in a crash.  The game will always keep going; it just takes it awhile.

When I first installed the game, it ran just fine with no problems.  Then I installed a Geforce 8600 gts with the 169.25 drivers, and it started acting up.  I've heard that the latest nVidia drivers have had problems, so could that be the problem?  Here are my system specs:

Intel Core2 Quad 2.40 GHz
2 gig RAM
Vista 32-bit
GeForce 8600 GTS (169.25 drivers)

I've also installed the Vista KB940105-x86 update.

Thanks for your help.