Ehm, what exactly do you mean with "blurred" ?
The Voodoo Rush does have Hardware cursor support, so any Mouse cursor (including custom ones, e.g. in Games) should be fine.
If it's broken (in terms of error pixels or lines, or even a complete Box of dynamic error pattern), this could indicate that the Video Memory Region normally reserved for the Mouse Image is being used for other purposes.
(I've seen this particular effect a couple of times, commonly it was either Bios related or the Driver was incorrect/needed to be reinstalled, or possibly indicated an IRQ/Resource conflict)
Nasty problem to troubleshoot, though , hard to nail down exactly