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View Full Version : FPS drops from 60 to 30



MickeyMouse
05-31-2002, 02:33 AM
does it also happen to you that the fps suddenly drops from 60 to 30 when there's more to display...
...and then you just don't display ONE small triangle and it comes back to 60...?

my fps is in 98% either 30 or 60 fps http://www.opengl.org/discussion_boards/ubb/smile.gif http://www.opengl.org/discussion_boards/ubb/frown.gif

is it maybe my card - 3dfx voodoo2 specific, or you get same strange results?

thx for replies

-- Mickey

harsman
05-31-2002, 03:04 AM
You have vertical sync enabled, i.e. the buffer swaps are synchronized to the vertical retrace of the monitor. If you take slightly longer than the time of one refresh (1/60 seconds seems like the refresh you use) you might end up waiting for most of a refresh until the buffer swap. If you time your code, you'll find that you spend a lot of time in Swapbuffers when you're running at 30 fps. Vsync can be disabled from your video drivers' control panel or with the swap hint extension in windows.