Recording N64 roms trouble

Hey I have some trouble recording gameplay on N64 roms. I use Mupen64 to do it, but currently it's not working right (games go VERY slow on it, and for some reason it only works maximised).
So does anyone know a better emulator/thing to record N64 roms to .avi or to convert another type of file to .avi ?
Or atleast to make Mupen64 run a bit smoother (my PC IS capable of it).
Thanks =]

recording games take a lot of cpu and ram. You need a pretty fast computer for it.

Pentium 4, 3.00GHz of CPU and 512 MB of RAM. Isn't that enough?