Umm, yes and no. -Windows- itself manages loading the files via it's virt mem, all Blitz does is tell Windows it needs to load it. What Windows does with it then, how it manages it, Blitz has no control over.
However, from the sounds of it, you actually mean what happens if vidmem is full... in which case, as I understand it, some sort of swap process goes on, if a graphic needs to be blitted something (hopefully a graphic that hasn't been used for a while) will be swapped out of vidmem and the new graphic loaded in. If this happens every frame (ie more than 4mb graphics used on a 4mb vidcard), expect to see some major slowdown. And of course that depends also on the PCI/AGP bus speed... 8xAGP is a wonderful thing. =]
However, from the sounds of it, you actually mean what happens if vidmem is full... in which case, as I understand it, some sort of swap process goes on, if a graphic needs to be blitted something (hopefully a graphic that hasn't been used for a while) will be swapped out of vidmem and the new graphic loaded in. If this happens every frame (ie more than 4mb graphics used on a 4mb vidcard), expect to see some major slowdown. And of course that depends also on the PCI/AGP bus speed... 8xAGP is a wonderful thing. =]