toma@sail.LABS.TEK.COM (Tom Almy) (03/22/91)
/ benyukhi@motcid.UUCP (Ed Benyukhis) / 11:26 pm Mar 12, 1991 / writes: > Recently I have downloaded an ATI video driver that provides and OEM > support for the ATI VGA Wonder to operate at full capacity under > MS Windows 3.0. I have had the driver installed and found that > the speed of the screen updates has decreased 5 fold. It has become > so slow that I was forced to revert back to the MS supplied standard > 640x480 VGA driver that is not capable of utilizing the board's > full potential. Does anyone have any suggestions???? Has anyone had > similar problems??? You are seeing several effects, and they are not specific to your card. 1. With more pixels on the screen you typically have to write more pixels to display the same information. For instance a full screen redraw on an 800x600 display will be 1.6 times slower because there are 480,000 pixels rather than the (640x480) 307,200 of a standard VGA. 2. If you use a 256 color mode you have twice as many bits per pixel as a 16 color mode, therefore there will be roughly twice as much data for an image of the same size. Again the speed will halve. 3. For any 256 color mode, and for the 1024x764 16 color mode, bank switching becomes tortuous and adds to the overhead. -- Tom Almy toma@sail.labs.tek.com Standard Disclaimers Apply