The cache should be at .local/share/Steam/SteamApps/common/Serious Sam 3/Temp/ShaderCache/ - but I give no guarantee that deleting these files won't damage anything!2. Serious Sam 3 doesn't start anymore :-(
I read, that deleting a texture cache might fix this, but I have no idea what file to delete (where?).
you could downgrade the driver.Any idea, how to fix the problems?