As a general rule, you should render only as large as your target delivery format requires. For NTSC video, 720x540 (square pixels) is all you need. For display on computers (web, download, etc.) 640x480 is standard. HD and film are much higher (1920x1080 and 2k+ respectively). A 1024x768 animation is simply too large. There's nothing that says you can't do it, but I think you're just wasting time and drive space to get that size. Also, you'll never get it compressed decently enough for reasonable file transfer times. But, if you want huge movies, more power to you. :p

Also, you can speed up render times by rendering at the command line. By using command line rendering, you don't have to load the entire Maya UI which can take up processor time. At this point, it also doesn't matter what video card you have.

Finally, Maya's renderer is incredibly slow. It gets even slower when you start adding fur, cloth, fluids, etc. Throwing raytracing on top of that pretty much kills any notion of reasonable render times.

One way to get around the slow render times is to render multiple passes and composite the elements in After Effects, Shake, Combustion, etc. It requires some planning and setup time, but when it comes time to tweak and re-render elements, it goes by a lot faster.