I'm using Debut to capture video, but the framerate's ***, even though i have a really beefy pc. Any ideas?

It seems like it's because it's not v-synced. Is there a v-sync option, because I can't find it.

I believe that option is available from the ctrl-F4 menu.

If I have the shortcut key wrong (my apologies first if so), then the menu I speak of is the same one as from the "Settings" and then "Graphics" options from the main startup menu.



(Sheesh! Must have the "verbose" button by mistake...)

It has nothing to do with vsync, and everything to do with the method you chose to use for video or frame output. Generally speaking, you won't be able to use the built-in capture tool while keeping high framerates inside the program, because the program will not render a new frame until the previous frame has been output and everything in the scene is loaded for the next frame. This ensures maximum quality and smoothness in the final video. If you want to record exactly what you see on the screen in real time, with quality being a secondary consideration, then use a program like OBS Studio to record video.