Possible to change the default 70hz refresh rate of 700x400 DOS resolution? \ VOGONS

Possible to change the default 70hz refresh rate of 700x400 DOS resolution?

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First post, by Nerevarine

Posted on 2026-01-27, 19:22

Nerevarine Offline

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Hello, I use HZ Tool on my Win98SE retro PC with a CRT display to increase refresh rates of various resolutions. However, it seems that the 720x400 DOS resolution’s default refresh rate of 70hz cannot be changed. It is not even listed in the HZ Tool and I have googled that not even VBEHz or Unirefresh tooly support this. Is there a safe and reliable way to change it?

Reply 1 of 5, by Nerevarine

Posted on 2026-01-27, 19:25

Nerevarine Offline

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There is a typo in the topic’s name. I meant 720x400.

Reply 2 of 5, by rmay635703

Posted on 2026-01-27, 19:39

rmay635703 Offline

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It’s text only and not a standard vbe selection.

So editing its refresh is more complex.

Also worth noting if you could lower it you would drop below the minimum VGA signalling rates which many screens can’t sync to.

There was a period in the late 80’s and early 90’s when certain svga systems had a bios setting to INCREASE the standard refresh rates but never saw one to lower it below normal VGA signal rates.

Reply 3 of 5, by maxtherabbit

Posted on 2026-01-27, 22:19

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There are TSRs which force 60Hz yes, moon and star

Reply 4 of 5, by rmay635703

Posted on 2026-01-28, 19:50

rmay635703 Offline

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maxtherabbit wrote on 2026-01-27, 22:19:

There are TSRs which force 60Hz yes, moon and star

Link?

I’m only familiar with vga60hz tsr and fastvid (mostly targeting doom or 320x200 dos games)

Text mode I remember having problems

Hmm, never noticed this one
https://steptail.com/guides:text_mode

Reply 5 of 5, by maxtherabbit

Posted on 2026-01-28, 21:13

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rmay635703 wrote on 2026-01-28, 19:50:
Link? […]
Show full quote

maxtherabbit wrote on 2026-01-27, 22:19:

There are TSRs which force 60Hz yes, moon and star

Link?

I’m only familiar with vga60hz tsr and fastvid (mostly targeting doom or 320x200 dos games)

Text mode I remember having problems

Hmm, never noticed this one
https://steptail.com/guides:text_mode

text mode can be handled with the command:
MODE CON LINES=43

this will force the EGA text mode which in addition to being 60Hz also avoids the classic sampling error that most digital sinks have with 720 (900px/line) timings

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