Obviously, the more power you throw at this engine, the better it looks
It's not always that obvious graphically. I've played plenty of games on the latest engines that looked only marginally better with everything set to maximum.
But then again perhaps this is merely a content issue.
From what I've read id have included enough polys into their D3 models to overburden the fastest of CPUs. I haven't though read much about how texture detail and lighting will scale depending on your video card. Will D3 off a GF FX really LOOK significantly better than D3 off a GF3 or GF4?
Perhaps we will have to wait for other devs to really push the new DOOM engine's capabilities.
"Nothing livens up a robotic hymn of doom more than an amazing pair of jugs." - Brak