VOGONS


First post, by vanfanel

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Hello,

I just got a relatively cheap, fanless, brand-less minipc from Aliexpress that has this old Celeron 2955U CPU.
It has Haswell graphics, apparently.

It's ALMOST good! It has some good things going for it in regards to native DOS:
-DOS boots natively: has good CSM support.
-EMS works perfectly well with EMM386 and JEMMEX!
-SBEmu works! So yeah, it has OPL and digital audio in DOS games and programs!
-Scrolling registers work well: Prehistorik 2 scrolling map is flawless, Superfrog works perfectly well, Jazz Jackrabbit also works well... That sums up my "test suite" for games which ask good DOS support to the hardware and it passes them all! Wow!

But here's the catch: it insists on using a 60Hz mode for 320x200 games, so some games like Lemmings 2, Tyrian, etc.. have slow music.

I know that there's the VGA60HZ TSR: https://github.com/wbcbz7/dos-vga-tsr-goodies … /master/VGA60HZ
...But what I would need is the opposite: I would need something that tells the CRTC registers that 320x200 IS a 70Hz video mode!
Is there such a thing? Can you guys shed some light here?

Thanks!

Reply 1 of 10, by keenmaster486

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Does your monitor natively support 70Hz? I don't know if there even is an LCD panel that supports 70Hz. Afaik they're all either 60 or 75, or something much higher.

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Reply 2 of 10, by vanfanel

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keenmaster486 wrote on 2026-08-14, 19:08:

Does your monitor natively support 70Hz? I don't know if there even is an LCD panel that supports 70Hz. Afaik they're all either 60 or 75, or something much higher.

I'm using an OSSC, it eats 70Hz for breakfast, so yes.
It seems to be something with the VBIOS on this PC, which as things are, insists that all DOS modes including VGA 13h (320x200@8) are 60Hz...

That's why I am looking to revert that via a TSR or similar.

Reply 3 of 10, by Falcosoft

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keenmaster486 wrote on 2026-08-14, 19:08:

Does your monitor natively support 70Hz? I don't know if there even is an LCD panel that supports 70Hz. Afaik they're all either 60 or 75, or something much higher.

Older LCD monitors that have analog/VGA input usually supports 70 Hz. I have 2 such monitors LG Flatron 2242T (1680x1050) and Philips 243V (1920x1080).

vanfanel wrote on 2026-08-15, 07:36:

I'm using an OSSC, it eats 70Hz for breakfast, so yes.
It seems to be something with the VBIOS on this PC, which as things are, insists that all DOS modes including VGA 13h (320x200@8) are 60Hz...

That's why I am looking to revert that via a TSR or similar.

You can only get 70 Hz from Intel HD on analog/VGA output and only in text modes (720x400 70 Hz). Unfortunately all lower resolution graphics modes are scaled to 640x480 60 Hz.
In case of digital output even text modes are scaled to 640x480 60 Hz.

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Reply 4 of 10, by vanfanel

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Falcosoft wrote on 2026-08-15, 09:40:

You can only get 70 Hz from Intel HD on analog/VGA output and only in text modes (720x400 70 Hz). Unfortunately all lower resolution graphics modes are scaled to 640x480 60 Hz.
In case of digital output even text modes are scaled to 640x480 60 Hz.

According to OSCC, text mode is also getting scaled to 60Hz.
This is over analog VGA output, of course: all DOS-capable computers I've seen only produce 60Hz when connected over HDMI.

But even so, shouldn't it be possible to program the CRTC so mode 13h behaves like actual 13h (70Hz)?
I mean, VGA60HZ does the opposite, so...

Reply 5 of 10, by Falcosoft

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vanfanel wrote on 2026-08-15, 10:00:
According to OSCC, text mode is also getting scaled to 60Hz. This is over analog VGA output, of course: all DOS-capable computer […]
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Falcosoft wrote on 2026-08-15, 09:40:

You can only get 70 Hz from Intel HD on analog/VGA output and only in text modes (720x400 70 Hz). Unfortunately all lower resolution graphics modes are scaled to 640x480 60 Hz.
In case of digital output even text modes are scaled to 640x480 60 Hz.

According to OSCC, text mode is also getting scaled to 60Hz.
This is over analog VGA output, of course: all DOS-capable computers I've seen only produce 60Hz when connected over HDMI.

But even so, shouldn't it be possible to program the CRTC so mode 13h behaves like actual 13h (70Hz)?
I mean, VGA60HZ does the opposite, so...

1. I have just checked this on my Haswell (i7-4770K) desktop and it outputs 720x400 70 Hz through analog VGA.

The attachment Haswell_VGA.jpg is no longer available

BTW, it seems to be real 70Hz. I used my retro PC with a CRT monitor as a reference and my Ivy Bridge T430 (it works the same way as my Haswell desktop under DOS) and run the famous 70 Hz test program YO! on both screens.
Here is the test video:
https://youtu.be/ZXDQM2MtTZE

2. Yes, but not all of them scale lower resolution modes to 640x480. E.g. Nvidia cards scale all modes to the native resolution of the LCD. This gives much better output quality for text modes. Text modes over digital output are very ugly on Intel HD.

3. The problem is the VGA BIOS does not handle it as real mode 13h. Instead you should try to force 640x480 70 Hz.

Last edited by Falcosoft on 2026-08-15, 20:29. Edited 1 time in total.

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Reply 6 of 10, by vanfanel

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@Falcosoft: Thanks a lot... It seems that the VBIOS on the mini-pc isn't good then 🙁
Time to return it. I have returned like 10 different ones already for different defects in DOS.
It seems that my dream of a modern mini-pc for DOS gaming is...well, a dream 😁

Reply 7 of 10, by mgtroyas

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Please share your findings in the future, I'm also very interested on this.

If only the size is the target, I'd suggest a USDT version of desktops like HP EliteDesk or the Dell Optiplex. I have Sandy Bridge based HP 8300 Elite and Dell Optiplex 7010 because they are the last ones with XP support (although the SFF size so I can use a dedicated video card) but I just booted on MS-DOS and there's no problem running 70Hz on the Intel integrated VGA. No idea what generation they may have lost that capability, would be funny to run DOS on a Optiplex 7090 or EliteDesk 800 G6 with an i5-10500t.

Reply 8 of 10, by Falcosoft

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mgtroyas wrote on Yesterday, 22:47:

Please share your findings in the future, I'm also very interested on this.

If only the size is the target, I'd suggest a USDT version of desktops like HP EliteDesk or the Dell Optiplex. I have Sandy Bridge based HP 8300 Elite and Dell Optiplex 7010 because they are the last ones with XP support (although the SFF size so I can use a dedicated video card) but I just booted on MS-DOS and there's no problem running 70Hz on the Intel integrated VGA. No idea what generation they may have lost that capability, would be funny to run DOS on a Optiplex 7090 or EliteDesk 800 G6 with an i5-10500t.

70 Hz on what output(s) and in what video mode(s)? The details can be important. On digital outputs 70 Hz under DOS was lost at the very beginning. Your Sandy Bridge cannot do such miracle either for sure.
But I can confirm that 70 Hz works in text modes on analog VGA output even on Ivy Bridge and Haswell. But 70 Hz in graphics modes definitely not.

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Reply 9 of 10, by darry

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I would not get my hopes up, but something like this might work to get 70Hz over DVI or possibly HDMI on some cards.

70Hz in pure DOS at 1600x1200 (or other) over DVI on an old card (FX5900) with modern monitor is possible

EDIT :
On older ATI cards, hex editing the vBIOS can work.
Outputting 720x400@70Hz with the ATi R300 DVI output in DOS

I have no clue whether either of these approaches might be viable on any Intel iGPU.

Reply 10 of 10, by mgtroyas

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Falcosoft wrote on Yesterday, 23:23:

70 Hz on what output(s) and in what video mode(s)? The details can be important. On digital outputs 70 Hz under DOS was lost at the very beginning. Your Sandy Bridge cannot do such miracle either for sure.
But I can confirm that 70 Hz works in text modes on analog VGA output even on Ivy Bridge and Haswell. But 70 Hz in graphics modes definitely not.

70Hz silky smooth scrolling on Prehistorik 2 on 320x200 video mode (and the other custom mode it uses for scrolling on difficulty selection and map view screens), over Intel integrated GPU VGA output, detected by my Samsung CRT as 720x400@70Hz as analog monitors cannot distinguish text mode from video mode, exactly as in era appropriate hardware. I used a bootable USB running Windows ME MS-DOS created using Rufus integrated option.