Benchmarked here all at 16Mhz, Cache on. One with NVDI and one without. I believe that with NOVA, NVDI acts only as a GDOS, so there's probably more lightweight GDOS alternatives out there. Something like 2.5MB ram free at boot, so 1.5MB used approx. 640x480 60Hz 256colour.
Sorry for the light reflection in the monitor. The graphics card is external; for now I pulled the whole computer to the front to make space for it, and it has to face the lamp.
Feels a lot slower than Atari graphics + NVDI, but average score is only a small bit worse. All individual scores are much worse except VDI Graphics which is very very fast. It's a shame, I liked how NVDI on Atari graphics has fast text, and this setup loses that.
I think there must be a lot of speed left to find in this hardware, if a programmer looks for it.