Refresh rate with Tridentchip 9440 AGI

Posted on 1997-10-26
Last Modified: 2007-02-13
I have bought a Trident SVGA Vesa card with the chipset 9440 AGI. (printed on the chipset TGUI
9440AGI, In/9438, B25389.1/Rev#27)

The Video Bios screen says TVGA Bios A 5.1 (55), 1024 K 32 Bit Bus Dram, VGA mode, Copyright
1994 Trident Microsystems, Inc., Copzright 1990 Phonix, F-B-16-V16-FOM
(This is all doubledutch to me. The only thing I am surprised about is the VGA mode. Shouldn’t that be
SVGA? And if yes, how do you change it? On the other I can run 24-bit colour in that mode, so maybe the
mode doesn’t matter.)

My screen is a 14 inch no name monitor. The technical specifications are as follows:
CRT:      14 Inch, 90 degree deflection
Phosphor Dot Pitch:      P 22, 031, mm/ 0,28 mm
Scan Freq:      Horizontal: 31.5 kHz/ 35.2 kHz (automatically)
      Vertical:   50-90 Hz (automatically)
Video bandwidth:      40 Mhz (-3dB)
Display Capability:      Up to 2400 characters (80x30 lines)
Color Display:      Unlimited
Display Area:
Horizontal:      240 mmm
Vertical      180 mm
Display Resolution: 1024 x 768

I have downloaded the correct driver for this chipset. I can run 256 colours, 16-bit and 24-bit colour at the
640x480 screen resolution. However, if I try to change my resolution to 800x600 (which I ideally would
like to run at) my screen is all jaggy lines. I suppose this has something to do with the refresh rate of the
card. At a resolution of 800x 600 the screen is split into approx. 20 horizontal bands with jaggy edges at
the border and the screen is just a wild mess.  If I run at 1024 x 768 these horizontal bands are only about
2 pixels wide and I can see the cursor and desktop items repeated several times along a horizontal line.
There is a refresh utility that came with the driver, because refresh rates have to be set manually. There
are seven different rates….I tried all of them out…Obviously none of them worked. Not only that, but
between the different rates, there is no difference. The screen distortion looks everywhere the same.

The Readme for the Refresh is the following:

This driver does not automatically configure the display adapter's
refresh rate according to the capabilities of the monitor to which
it is attached.  Instead, the refresh rate must be manually set.
To do so, follow these steps:

1. Copy the SMONITOR.EXE utility into it's own subdirectory.
2. Boot Windows 95 to a Command Prompt (restart the machine
    and hit F8 when the "Starting Windows 95" message is
3. Run the SMONITOR utility from the Command Prompt. All available
   refresh rate groups will be displayed.
4. From the list of refresh rate groups, decide which one you will
   use. Type "SMONITOR X" at the Command Prompt, where X is the
   refresh rate group number you have chosen.
5. You can now start Windows 95 by entering WIN and the Command

(I followed those instructions - without much luck)

If you call up Smonitor.exe  you get the following screen:

GROUP      TYPE      600x400      640x480      800x600      1024x768      1280x1024      1600x1200
0      31K      70      60      56      87i      87i      87i
1      35K      70      72      60      87I      87i      87i
2      48K      70      75      75      60      87I      87i
3      57K      70      75      75      70      87I      87i
4      65K      70      75      75      75      60      87i
5      72K      70      85      75      75      60      87i
6      82K      70      85      75      75      60      87i
7      100K      70      85      75      75      60      87i

command: smonitor (group|option)

option:      c: colour display
      m: monochrome display

I don't know what the ascending memory specifications under type refer to. My card has 1 MB RAM
onboard. So does this have an impact on which type I have to chose? I have also tried different groups
with the option for colour display together but this didn’t have an impact either.

Driver information (from Display Properties>Adapter)

Trident TGUI 9400 Cxi, Linear Addressing For ISA/VL V1.0
Manufacturer: Trident Microsystems
Chip Type:  Trident
DAC Type: Internal
Memory: 1MB
Software Version: 4.0
Current Files: trident.drv, *vdd, *vflatd, trident.vxd

Refresh rate: Adapter Default (also available Optimal)…
There is no difference between Adapter default and Optimal either.
What do these two choices affect?

Monitor (in Advanced Display Properties) is set to

Super VGA 1024 x 768
Reset display on suspend/resume is checked.

Has anybody any suggestions how to get this card running in 16-bit or 256 colours at 80 x 600 res.? I
would be really thankful for help? Does anybody know of a generic refresh utility that may also do the job?
I hope I haven't held you up too much with all this, but I thought I write it down as detailed as possible, so that you don't  have to keep asking for more information.
Question by:pietsch
  • 3

Author Comment

Comment Utility
Edited text of question

Accepted Solution

eugenem earned 100 total points
Comment Utility
These numbers in kilobytes in group descriptions are horizontal scan frequencies, not memory sizes. You have to choose group 0 or 1 because your monitor have horiz. scan frequency of 31/35 KHz. You should add call to "smonitor 0" (or smonitor 1) to autoexec.bat. Try to change your monitor to 800x600 SVGA (in Advanced Properties).

Author Comment

Comment Utility
Eugenem, thanks for the info, I tried to run the card at 800x600 which works fine. Then I changed smonitor to smonitor 0 and 1 and it gave me the same jagged horizontal bands on the display?

Do you have any other suggestions?

Author Comment

Comment Utility
Thanks for the info, but unfortunately it didn't work. I changed the screen res to 800 x 600 and then added the smonitor 1 line to my autoexec.bat. Result: the same jagged horizontal bands. Do you have any other suggestions?


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