When I use Doomsday 1.x in a large area, like in the large room in The Gantlet in Doom 2, I seem to stay at a nice solid 85fps... Looking at MSI Afterburner my GPU usage is pretty good and my card's core clock goes into gaming mode and memory clock goes to 3Ghz like it is supposed to.
In Doomsday 2, same room, I get 19fps, and my GPU is staying in low power mode, like it's not even being utilized. I did use a utility that set my GPU to use full power at all times, it did nothing to the framerate and GPU usage was almost 0%.
I'm not sure what's going on there, or how to fix it.