The Viper v550 is a TNT-based video card, so generally speaking, your Monster-II card will be the better performer of the two so yes, you should use it for any games that will allow you to. Generally, the Voodoo card will automatically over-ride your other video card, so it shouldn't be a problem. Just a tip, if you see 3dfx or glide as a video option you should select that mode. For Unreal, the first time you run it after installing or patching it should ask you if you have a voodoo card installed and just answer yes. If you are already installed and patched, go under options, advanced, drivers, and for video select glide. (I'm doing that from memory, so my menu names may be slightly off)
FYI: Monster II (voodoo2) can use 3dfx glide mode and direct3d mode (glide faster).
Viper v550 can use direct3d mode and OpenGL mode. If you select direct3d (d3d) mode, the voodoo card automatically takes precedence. Only mode that will default to Viper550 is OpenGL. Hope this long-winded post clears some things up for you without putting you to sleep...
[This message has been edited by The Toastman (edited 04-20-2000).]