Actually the VideoRam option is not always needed (some rare drivers ask for it) it's usually measured by X when it starts.
By the way RenderAccel option really speeded up X when testing xcompmgr effects so I have it turned on by default, try:
Code:
Section "Device"
Identifier "VESA Framebuffer"
Driver "nvidia"
Option "NoLogo" "1" #This skips the Nvidia logo when X starts
Option "RenderAccel" "1" #May improve performance, it did for me ;)
EndSection
