That TSR can only reprogram some of the video timings related registers of VGA hardware so that you get 60Hz = 480 lines to the monitor from the usual 70Hz = 400 lines (low resolutions like 320x200 are line-doubled).

There is no support for stuff like vertical stretching on the VGA hardware, and the game still thinks it is in the usual 70Hz mode so you are likely going to see fun stuff like that when using it. At best there could be black bars at top and/or bottom but definitely not a stretch to fill the screen.

If the card was connected to the monitor digitally (using DVI or HDMI), the monitor would probably scale the active picture to fit the screen (hiding the blanking area). But it's also likely to get stretched horizontally because the digital transmission methods have a minimum dotclock speed and use pixel repetition to ensure it is met.

Interesting, thanks. Yeah, I can use the /blankfix switch to black out the blanks but then it’s just a smaller video area in the middle of the screen.

I do have another retro machine hooked up by DVI to the same monitor and it does respect 4:3 in DOS when the monitor is set to preserve aspect ratio. Strangely, when it is in that mode, it shows that 320x200 games are 1280x1024, so it must be a nice multiple or something. On the VGA machine, it detects text mode and preserve aspect is disabled in monitor menu.

I thought maybe the DVI had something to do with it. I tried a few VGA out to DVI in adapters, and learned a few lessons about DVI-I vs DVI-D the hard way. DVI-D doesn’t work because it lacks the analog pins. Haven’t tried a DVI-I adapter, but I’m assuming it will do nothing differently than the VGA.

I guessing it also may have more to do with the card itself and what it’s outputting compared to just the connector. The DVI machine has a newer GeForce card. If I use VGA off this card, I get the same result as the older machine.

I also tried a VGA out to HDMI in adapter, which works fine in Windows but won’t display anything during BIOS or in DOS so it’s kind of useless. Not sure if it’s that particular adapter or a common issue where VGA-HDMI can’t recognize DOS resolutions.

Majority of those adaptors cannot do 70Hz, which is why they show nothing in DOS.

For anyone interested, I finally found a cheap adapter that works in DOS after the 4th try from Amazon. I was combing another post and found another member had an adapter shaped similar to this one that worked, so I thought it may be a clone.
https://a.co/d/7epaLgl

It’s not perfect though. It sometimes gives diagonal interference lines on dark screens. Strange that it appears to only do it when at 640x480 60Hz, or in Text Mode. I tried moving the USB supply power from the PC port to a power block on the wall, but didn’t seem to help. If I switch through every other resolution, there is no issue so it’s probably not a power noise issue. Weird thing is that it is sporadic, a few times I was able to start Quake in 640x480 without the lines, but they will show up the next time I switch to that mode.

It seems like it sets the monitor to h=31.3khz v=70hz instead of a real resolution when in DOS text mode or 320x200 game. I can also tell the aspect is not correct. It is stretching a little wider than 4:3 in this mode.