slow response in fullscreen mode

[ametamorphosis]

here is the text from my dxdiag tests
The file 3dfx16vb.drv is not digitally signed, which means that it has not been tested by Microsoft's Windows Hardware Quality Labs (WHQL). Current drivers tested for a WHQL logo are only available on Windows ME, Windows 2000, and Windows XP. New Windows 98 drivers are no longer tested for WHQL logos.
DirectDraw test results: All tests were successful.
Direct3D 7 test results: All tests were successful.
Direct3D 8 test results: All tests were successful.
Direct3D 9 test results: All tests were successful.

i am using a 3rd party driver for my card, as it is no longer supported by the manufacturer. i have had no issues with more intensive programs such as quake 2/quake 3