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From: rommel@Informatik.TU-Muenchen.DE (Kai-Uwe Rommel)
Newsgroups: comp.os.os2.misc
Subject: Re: 72Hz VGA Card Recommendation Sought
Message-ID: <1991Jun27.184407.27404@Informatik.TU-Muenchen.DE>
Date: 27 Jun 91 18:44:07 GMT
References: <1991Jun27.021511.1862@midway.uchicago.edu>
Sender: news@Informatik.TU-Muenchen.DE (System)
Organization: Technische Universitaet Muenchen, Germany
Lines: 40

In article <1991Jun27.021511.1862@midway.uchicago.edu> sip1@quads.uchicago.edu (Timothy F. Sipples) writes:
>- must have 72Hz vertical refresh in standard VGA modes (plus 640x480x256);
>- 512K;
>- 16 bit;
>- must have 60Hz (not 56Hz) vertical refresh in 800x600 modes;
>- support for OS/2 1.3 PM in above modes (16 color -- 256 color possible?)
>  with above refresh rates;
>- well supported otherwise.

>Do all Trident 8900 boards perform the above feats?  Do all Tseng Labs ET4000
>boards perform the above magic?

It depends on the card AND driver. The Trident 8900 card I tested
recently was DIP-switchable between low refresh rate and interlaced mode
for cheap displays and higher refresh rate and non-interlaced operation
for more expensive displays and the OS/2 1.3 drivers I tested recognized
these settings and worked in both modes as expected. But I found that
even with high refresh rate it still flickered a bit (I think it had
about 60-63 Hz at 1024x768x16).

Different to this, the ET4000 driver always programs the chip itself
and works in 800x600 with about 70 Hz and in 1024x768 with about 66-68
Hz non-interlaced. I can tell the difference because I have a 8514/A
that works with 70 Hz non-interlaced at 1024x768. I have a STB Tseng
4000 card which is in interlaced mode when powered on but the PM driver
immediately came up with non-interlaced mode at the high refresh rate on
this card. Also, the image size was a bit different than in the DOS-used
BIOS-based mode. When using an ET4000 card with these drivers, make sure
you have a display that can synchronize up to 58 kHz !!! A NEC 3D will
not even work in 800x600 with this driver !!!

>I'm one of those unfortunate people who get see flicker fairly easily.
I'm one too.

Kai Uwe Rommel

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

DOS ... is still a real mode only non-reentrant interrupt
handler, and always will be.                -Russell Williams