I just bought the game from GOG, an old favorite that I got completely by accident at the time.
However, as I loaded the Tutorial, it was all fine at first. Then, after my second talk with the homuculus the framerate starts to drop and graphical glitches start to dominate the screen.
So I take the resolution down a couple notches to 1600 by 1200 and try again. This time I get to walk all the road down to the ruin before the glitches make the game unplayable.
So I went to the NVidia control panel and disabled the anisotropic filtering and anti-alising. This time I get all the way to casting a wrath spell at a locust before the game gives up on me. So it looks that for every downgrade I do in the graphics, the game just lasts a little bit longer, or maybe not even that, as I just skip the dialog I already had, still haven't tested if it is making any difference at all...
So, if anyone knows the configurations that'll let the game play smoothly in windows 7 and NVidia, could you lend me a help?

Same Problem here on a win7rc nv 8400. I think if you could to run it in software instead of using hardware acceleration it would run smoothly. I tried to find a way to run it in windowed mode but couldn't. maybe you could have better luck.

Also having this problem. It seems the combination of Win7 and Nvidia isn't good for this game.

I have this same issue as well. It's a great game though! I hope they get this sorted out someday =)

yeah I'e been having similar problems and have skipped through to tutorial 3 and it seems to be a problem with having multiple units in view as I get to the point I can summon a manahoar and thats fine but when I summon a second it pretty much stops working untill I send them out of view.

Same problem here, I can play for about 30 minutes before it crashes. Oddly enough an indicator that it's going to crash is that souls stop appearing. At that point if I save and reload I'm ok.
I think there must be some memory leak hanging around.

If you are using Nvidia Graphics Cards ---> Go into Nvidia Control Panel Settings and under "Manage 3D Settings", enable or turn on "Extension Limit". Hopefully this helps Thank you!!
Drop by the Sacrifice lobby sometime and make sure to visit www.sacrificeplanet.net
Cheers!

It was ok for me when I started the game selecting the option that was something like "hardware 3d" rather than "hardware 3d T&L".