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From: rommel@lan.informatik.tu-muenchen.dbp.de (Kai-Uwe Rommel)
Newsgroups: comp.windows.ms.programmer
Subject: Re: 256-color drivers are NOT always slower than 16-color drivers
Message-ID: <5398@tuminfo1.lan.informatik.tu-muenchen.dbp.de>
Date: 7 Nov 90 14:14:07 GMT
References: <3537@gmdzi.gmd.de>
Sender: news@lan.informatik.tu-muenchen.dbp.de
Reply-To: rommel@lan.informatik.tu-muenchen.dbp.de (Kai-Uwe Rommel)
Organization: Inst. fuer Informatik, TU Muenchen, W. Germany
Lines: 36

In article <3537@gmdzi.gmd.de> strobl@gmdzi.gmd.de (Wolfgang Strobl) writes:
>As far as I know, the cheap SVGA cards run the 16 color
>modes with 8 bit wide video ram access, even if they are
>16 bit cards and sit in a 16 bit slot. For the 256 color modes,
>this changes, these modes allow real 16 bit access.
>
>Because of this, I don't see why there should be much speed
>difference between 16 color and 256 color drivers of identical
>resolution. I did a little bit of research to check this out.
>
>
>Environment
>
>   Noname 386/25 cache, 8MB
>
>   Optima 1024A Plus (Tseng ET3000 based 16 bit card)

It may be that on the Optima VGA, 256 color mode is not much slower than
the 16 color mode because the 16 color modes of this card are *REALLY*
slow. A friend of mine had such an Optima VGA plugged into the same
board as I am using with a Paradise VGA-1024. The Optima card was that
slow that he returned the card to the dealer and got his money back.
For example, the Optima VGA was in 800x600x16 mode MUCH slower than my
Paradise VGA in 1024x768x16 mode. In same modes, it was a factor of
about 3 in speed. Therefore, when I assume that the 256 color modes are
not that different, you don't see so much difference. On my Paradise
card, the 256 color mode is indeed so slow in Windows (compared to the
800x600x16 mode) that I use it only for WinGIF.

Kai Uwe Rommel

--
/* Kai Uwe Rommel
 * Munich
 * rommel@lan.informatik.tu-muenchen.dbp.de
 */