Lower settings. Sorry, thats all there is to it. 8GB is not a lot these days (i have two older cards in my PC and they're both 12). Textures, screen resolution, there's a bunch you can do.
Crashes are unavoidable, given that everyone wants max performance everywhere, things get shipped with all the debugging and checking stripped.
The sort of protections that you're offered by your CPU and modern OSes aren't offered by GPUs and their libraries, yet. So you're back in the '80s, when your Mac or MS-DOS machine would crash hard on the smallest issue. That's life, I'm afraid.