Animations actually run at a constant speed too in 3DGS. The problem I have is that the frame rate seems to lock on powers of 2 and it doesn't remain constant as it has very noticeable jerks, about 3 or 4 per second where the jerks are caused from skipped frames due to running at a higher frame rate than my monitor's refresh rate. In most cases, this isn't an issue. For my 2D game, designed for 60 fps exactly like classics, it is an issue.

My only two possibilities that I can come up with is to reinstall 3DGS (deleting the entire GStudio6 folder). Another possibility is to download and run the older 6.22 engine (of which I don't think handles 24-bit images, a requirement).

Then, once I release my 2D game, you can download it (the free edition) and see the jerking effect yourself.