Not sure about that as the removed 2.30.3 test build didn't resolve the fundamental cause of the issue now I know what was going wrong. As there's a number of changes present in the current beta builds (soon to become a new preview build) that get Milkdrop (& potentially some other visualisations) running correctly again by managing the timer resolutions in a more consistent manner.
Without those changes (or ensuring each plug-in does it on its own) we get the issue that was reported in this thread due to the frame pacing waits varying too much & that is why it was running below 60fps or occasionally above 60fps. As the default OS resolution is around 15.6ms & with what was going on it could mean you'd get the next frame around the time wanted or it might have to wait for the next wait cycle (i.e. waiting ~31ms) which makes it hard to hit the desired 60fps (or other rate) targets.
-dro