AGP, Windows and Blitz3D manages your memory - don't worry. VRAM and AGP downloads and uploads textures and geometry all the time... but if you have some memory left there is no need to manage it. So basically if you don't use much big textures even 16meg will be okay. If you use constantly more VRAM than you have the AGP swapping will make things jerky and you need more of it to be able to play smoothly. Also note that higher screen resolutions will take bigger chunk of your VRAM permanently... I posted recently formulas how to calculate VRAM usage, it's here somewhere...