It's much faster to use the Radeon with the Mediator but it will only do 2D in OS3.9 so no Warp3D however you can always have a dual boot setup and use the CVPPC for your Warp3D stuff like Quake/Wipeout2097. (You wont be able to have CGX4 and Picasso96 running together so no live swapping of cards/screens, I tried it!)
You are right to say you can use Radeon Ram as Fast Ram but only on OS3.9.
The Radeon however is Warp3D compatible when you use it in OS4.1 Classic and will also give you the really cool hardware accelerated transparency.
For OS3.9 the best option would be a Voodoo 3 on the Mediator as you can then use Warp3D and it would be faster than the CVPPC however OS4.1 Classic Sux with anything less than a Radeon (run out of VRAM too quick) and you can't use two PCI graphics cards at once (OS4.1 wont even boot so that rules out having a triple boot setup!)
