On certain computers, one of the Windows 10 updates, perhaps the anniversary update, slows the frame rate in ZC and ZQuest. Even computers that have plenty of processing power to run these run at below 60 fps. It's as if the frame rate is just being capped too low for some reason. ZC runs at about 50 fps, while ZQuest runs at 25 fps.
For the ZC player, I've found that enabling VSync fixes the issue. Other people have had some success in messing around in the ag.cfg file. But for ZQuest, I've found no such fix. This happens in 2.5.2, 2.53, and 2.55, (and I presume all other versions).
Now here's where it gets weird. I tried tampering with the Intel Graphics Settings, and while none of the settings helped, having the graphics control panel open increases the fps to 60. But only on certain tabs. Other people have reported that having a video playing in the background increases it for them. It's almost like there's a higher graphics performance mode that gets triggered by certain programs or processes running, resolving the issue.
Has anyone else encountered, and hopefully fixed, this? Unlike the player, ZQuest is at least useable this way, but it gives inaccurate previews of animations, and makes scrolling around the map viewer a slog.