The CL-GD5429 predates Windows 95 even, so I think the Microsoft-provided driver is the only one around.

Are you using a CRT or LCD?

Even if you don't use Unix, there is some pretty technical information in the XFree86 FAQ for Cirrus video card users. https://www.xfree86.org/3.3.6/cirrus.html
In particular, 1024x768 87Hz interlaced would require a 45 MHz dot clock, while 1024x768 70Hz non-interlaced would require a 75 MHz one, and while the CL-GD5429 can apparently do 85 MHz at 256 colors, there is also something about the memory speed MCLK getting involved...

If you want to keep digging into it, you could install a Linux distribution from that era like Red Hat 6.2 or 7 and mess around with XF86Config and maybe get a better idea of your problem. But the trade-off for their cirrus driver providing so many knobs to turn is that it had an obvious reputation for being hard to set up.

Also, what kind of monitor does Win98 think you have? It will restrict the choices of refresh rates if it thinks your monitor can't handle them.
I assumed the "light strobing" effect was something deeper than the refresh rate at 800x600 defaulting to 56 Hz. Is it?

I'm using the predecessor.
CL542X/SOJ/SMT VESA LOCAL BUS REV 1.0
FCC ID # KDECL5428SMTHFVGA

Although there is 5428 in the FCC ID it uses a Cirrus Logic 5249.
The board looks like yours except the memory type in bank 0.
My memory is 45ns in bank 0 and 50ns in bank 1.

May I have a dump of your VGA BIOS please?

jakethompson1 wrote on 2021-10-04, 00:18:

The CL-GD5429 predates Windows 95 even, so I think the Microsoft-provided driver is the only one around.

Are you using a CRT or LCD?

That makes sense, I’m using a CRT, tried a few different refresh settings and 75Hz. Although the monitor keeps reporting the same 60hz no matter what I change in 800x600. Let me load the correct monitor profile and see what happens.

Disruptor wrote on 2021-10-04, 00:43:

May I have a dump of your VGA BIOS please?

Certainly, give me just a day or two.

Loaded the monitor driver for my NEC FE991SB and still the same. It seems 800x600 is stuck at 60Hz and 1024 is stuck at 87Hz, according to the monitor, regardless of changes made in Windows.

Chadti99 wrote on 2021-10-04, 01:07:

Loaded the monitor driver for my NEC FE991SB and still the same. It seems 800x600 is stuck at 60Hz and 1024 is stuck at 87Hz, according to the monitor, regardless of changes made in Windows.

Including switching to 256 colors?

jakethompson1 wrote on 2021-10-04, 01:20:

Chadti99 wrote on 2021-10-04, 01:07:

Loaded the monitor driver for my NEC FE991SB and still the same. It seems 800x600 is stuck at 60Hz and 1024 is stuck at 87Hz, according to the monitor, regardless of changes made in Windows.

Including switching to 256 colors?

Ah yes, good point, it hits 75Hz at 256 colors and isn’t interlaced. Actually I can change between 60, 70, and 75 and it actually hits those rates in 256 colors.

Chadti99 wrote on 2021-10-04, 01:27:

jakethompson1 wrote on 2021-10-04, 01:20:

Chadti99 wrote on 2021-10-04, 01:07:

Loaded the monitor driver for my NEC FE991SB and still the same. It seems 800x600 is stuck at 60Hz and 1024 is stuck at 87Hz, according to the monitor, regardless of changes made in Windows.

Including switching to 256 colors?

Ah yes, good point, it hits 75Hz at 256 colors and isn’t interlaced.

Nice. If you really do want to push the 5429 to its limits I would recommend playing with Linux where you have super fine grained control over everything. The 5429 is a Windows 3.x era card, so I doubt people cared much about its capabilities when running with > 256 colors, or > 800x600 resolution. Remember all those 90s educational games that would force you to switch to 256 colors when opening them? Supposedly the GUI acceleration capabilities on these cards often work slower or not at all when not in 256 colors. Haven't dug into the details.

jakethompson1 wrote on 2021-10-04, 01:30:

Chadti99 wrote on 2021-10-04, 01:27:

jakethompson1 wrote on 2021-10-04, 01:20:

Including switching to 256 colors?

Ah yes, good point, it hits 75Hz at 256 colors and isn’t interlaced.

Nice. If you really do want to push the 5429 to its limits I would recommend playing with Linux where you have super fine grained control over everything. The 5429 is a Windows 3.x era card, so I doubt people cared much about its capabilities when running with > 256 colors, or > 800x600 resolution. Remember all those 90s educational games that would force you to switch to 256 colors when opening them? Supposedly the GUI acceleration capabilities on these cards often work slower or not at all when not in 256 colors. Haven't dug into the details.

Got it, so maybe just a limit of the card or the windows driver ?

Chadti99 wrote on 2021-10-04, 01:41:

Got it, so maybe just a limit of the card or the windows driver ?

Maybe. Looking at the .inf file, you can try poking around in the registry. I haven't tried this on real hardware.
Compare
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Display\0000\MODES\8\800,600
vs.
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Display\0000\MODES\16\800,600

Seems the former has a list of valid refresh rates while the latter is empty...
Don't know if it will do anything to copy that list to the \16\ and \24\ values though.

Yes, fantastic idea! I’ll give it a shot tomorrow.

Even with 2MB RAM on paper it should support higher colours at higher resolutions, but it would be the RAMDAC that's the limitation here. I've been playing around with a few VLB cards recently in Windows 3.1 (ET4000 W32i 1MB, ARK1000VL 2MB, Cirrus Logic something 2MB), apart from only the highest end VLB cards you won't get much above 800 x 600 at decent refresh rate. They're all terrible 1024 x 768 and above.

Byrd wrote on 2021-10-04, 02:57:

Even with 2MB RAM on paper it should support higher colours at higher resolutions, but it would be the RAMDAC that's the limitation here. I've been playing around with a few VLB cards recently in Windows 3.1 (ET4000 W32i 1MB, ARK1000VL 2MB, Cirrus Logic something 2MB), apart from only the highest end VLB cards you won't get much above 800 x 600 at decent refresh rate. They're all terrible 1024 x 768 and above.

Got it, yah this is my first experience with a VLB card so all new to me, it’s easy to forget how old they are. Should I not be able to get higher than 60Hz at 800x600x16bpp?

This answers some of my questions. Doesn’t look like a non-interlaced mode is possible at 1024x768 above 256 colors.

yep.

Programmable dual-clock synthesizer
— Pixel clock programmable up to 86 MHz

There's a whole whack of drivers and tuners to play around with here... http://files.mpoli.fi/hardware/DISPLAY/CIRRUS/

Disruptor wrote on 2021-10-04, 00:43:

May I have a dump of your VGA BIOS please?

Hi Disruptor, any advice you can provide on dumping roms? I’ve got a TL866II-Plus and the rom chip from the card is a Winbond W27F256-10 part but I don’t see this option in Xgpro. Any help is appreciated.