The Graphic-Cards (GC) do render to screen with dramatic speed. You will wonder why this doesn't speed up rendering your image as well when using 3D Studio Max. This is because of how the (standard PC) hardware works and Max is not using a hardware-renderer.
Simplified: The CPU sends it's data from the System-RAM to the GC. The GC renders an image out of what it gets and sends it to the screen (at usually around 72dpi) - not back to your system's RAM, since the out-port of the GC is (mainly) a oneway-road. Therefore the system can't access the rendered image that is sent to the screen.
3D accelerators are usuefull to speed up the viewports. The faster the GC tells the screen what to do, the faster - and smoother - the handling of the viewports will become. You surely noticed the degradation that occures when handling certain views of certain models. Trying to (eg.) rotate a huge and complex scene in "shade and highlight" mode often degrades the display to wireframe or even to bounding box while rotating. Switching on "degradation override" may make the viewport behave somewhat stubborn to your commands. This is where a fast GC comes handy. Also doing previews of animations in viewports will benefit from an accelerated GC.