My computer specs (laptop):
Intel Core i5-3210M @ 2.50 GHz
4 GB RAM
Intel HD Graphics 4000
I can now run on 640x480, Lowest setting, VSync Off for 60fps. Occasional dips to about 55fps on Snow Mountain stage. I can play on slightly higher resolution (800x600) on some stages such as Valerie’s (and possibly Sanctuary or Tavern). However, for consistency sake across the board, I leave it on 640x480.
Love it since I regularly dipped to 40fps (or lower) on 512x384 when I played online before the December 2017 update!
Edit: Another point of reference.
Intel Core i7-950 @ 3.07 GHz
NVIDIA GeForce GTX 760
1920x1080, Highest, VSync Off. Regularly around 100+ fps.