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First post, by procerus

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I've just upgraded my GeForce2 GTS to a GeForce 6800GT and very nice it is too.

But there's always a fly in the ointment. 😒

In this case the problem is that UniRefresh no longer works. This means that my DOS games (which I prefer to play in DOS proper) like Flight Unlimited, Duke Nukem 3D, Blood and so forth no longer run at an acceptable refresh rate. I used to run them at 85Hz and now they run at 60Hz.

The problem appears to be that UniRefresh is ignored. If I enter the TSR's setup mode all the test functions also default to 60Hz no matter what refresh rate I specify.

Does anyone have any similar experience or any suggestions?

I did a search for a similar utility and found VBEHZ but it suffers from the same difficulty.

If anyone has any clue how I could contact Rob Muller (UniRefresh's author) that would be appreciated too! He was always a marvellously helpful and capable person!


98lite with 629K of free conventional memory in full DOS mode using QEMM 9.0 (or 628K with UMBPCI.SYS providing real mode for FastVid) with SmartDrive, CD-ROM, CuteMouse, sound support and UniRefresh all loaded high.

Reply 1 of 7, by priestlyboy

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http://web.archive.org/web/20021003001657/htt … .com/index.html
Unirefresh Homepage before it disappeared from the net.

Email -> rob.muller@gmx.net

Thanks to the Waybackmachine.org I was able to look it up for you. I've never used the program.
Never heard of it either but maybe you can get in contact with him.

Helping Debug DOSBox.

Reply 2 of 7, by Jiri

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procerus wrote:

In this case the problem is that UniRefresh no longer works.

I am really curious what response you will get from Rob Muller, let us know, please. I could change VESA refresh rates with Hercules GeForce 2MX in DOS/Windows XP with UniRefresh or VBEHz, but I had same problem as you with GeForce FX5200 Inno3D. I made some enquiries in that matter several months ago. Of course, I got no reply at all from InnoVISION support (they already have my money so why would they bother 😠), but Gerhard Strangar (creator of freeware utility VBEHz) replied immediately (you can find his e-mail address in readme of VBEHz). It did not solve my problem though - he mentioned that there is probably some bug in my card bios and recommended trying other bioses, but I could not find any that would work.
I switched to ATI card then and even if it does not have VBE 3.0 support so UniRefresh or VBEHz cannot work with it, it was possible to change DOS refresh rates settings in bios with Radedit1.1d editor. I know that there is also bios editor for NVIDIA cards available, but unfortunately without possibility to change DOS refresh rates.

Reply 3 of 7, by procerus

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I'm sure Rob won't mind if I post his reply to my question about this matter since it may be of interest to others on this forum.

I think it has been around 2 years since I removed the ms-dos development
environment from my system and moved on. I am not a gamer myself and I have
not used any of my dos programs for a long time.
I noticed that UniRefresh (at least the setup program) does not work under
Windows XP with my machine (P4 3GHz), I am not sure what the problem is.
When booting from a dos-floppy it works but my NVIDIA FX5200 only works at
60Hz, this is probably the same problem you are experiencing. I guess the
video card BIOS ignores the VBE 3 refresh rate changes. It is probably
extremely hard (if not impossible) to do anything about this.

Currently I am using a TFT monitor and refresh rate problems do not exist
anymore. After receiving your email I have started testing my monitor with
the test screen from the UniRefresh setup program. I noticed that all
resolutions looked bad using the DVI cable. When selecting the analog cable
(available with one knob on the monitor, DELL FP2001, 20"), every
resolution looks really sharp (the native resolution of the monitor,
1600x1200, is not supported by the video card as a VESA mode). It is really
surprising that the analog connection is that much better than DVI (this is
caused by the monitor). I did not expect that a TFT could look that good at
resolutions other than the native resolution, it looks fuzzy with the DVI
cable but sharp with the analog cable.

Maybe it is a good idea to buy a TFT monitor instead of a graphics card? I
don't think every TFT does such a good job on scaling as my monitor though.
The response time of my monitor is not as good as with a CRT but it looks
good enough when watching video/TV (I am one of the DScaler developers,
http://www.dscaler.org, I watch a lot of TV on the monitor).
I can recommend the Dell FP2001, especially since it seems that it costs
only 60% in the USA of what I have paid for it last month.

To be precise, the resolutions that I have tested on my monitor are:
- with the analog cable (sharp) and the DVI cable (fuzzy):
the dos text screen (IIRC 720x400)
- both cables equal quality:
1024x768 (sharp)
12080x1024 (fuzzy)
1600x1200 (sharp)




So it looks like the problem with nVidia's later cards is that VESA specific code in the card's BIOS no longer recognises calls to change the refresh rate. So us nVidiots are stuck with 60Hz in DOS.

I appreciate Rob's suggestion that this can be fixed by switching to a TFT monitor. And seeing that some of them are now supporting a decent range of low resolutions I would do so. Except in my case I play a lot of games with 3D stereo glasses and these don't works with LCDs. 🙁

My thanks to Rob for producing UniRefresh in the first place and thereby providing me with hundreds of hours of 85Hz refresh rate DOS gaming. Thanks to him also for providing me with excellent support even to the extent of producing custom TSRs to support specific games.

For myself I may have to either get on with building that "legacy" system or else think about installing dual monitors.


98lite with 629K of free conventional memory in full DOS mode using QEMM 9.0 (or 628K with UMBPCI.SYS providing real mode for FastVid) with SmartDrive, CD-ROM, CuteMouse, sound support and UniRefresh all loaded high.

Reply 4 of 7, by thierrybo

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Just my two cents about this very old thread. I am experiencing this 60hz problem when running DOS games in Windows XP command line mode, and unirefresh does not help too, BUT :

I discovered that running these games through DOSBOX in fullscreen mode they run at a higher refesh rate. I get refresh rates ranging from 70hz to 100hz 😀 😀

Reply 5 of 7, by dvwjr

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thierrybo wrote:

Just my two cents about this very old thread. I am experiencing this 60hz problem when running DOS games in Windows XP command line mode, and unirefresh does not help too, BUT :

I can also confirm that the NVidia 6600GT (Leadtek PX-6600GT) does not work with UniRefresh v1.42 under MS-DOS v6.22, the BIOS seems locked to 60Hz on a CRT monitor. The (S)VGA registers to change the clock rate ARE functioning, since the 60Hz refresh rate is constant at all VGA and SVGA graphics modes. The text modes are at 70Hz. The recent NVidia video adapters simply do not allow VESA Int 10h calls to go above 60Hz in graphics modes and 70Hz in text modes.

This makes sense from NVidia and its partners from a support perspective, many of its customers use flat screen LCDs (vice CRTs) and would not take kindly to an 85Hz input. So NVidia locks in the traditional 60/70Hz limits and avoids any support headaches...

Too bad they did not used one of the reserved VESA Int 10h functions to allow this behavior to be modified.


Reply 6 of 7, by gerwin

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This darn issue, got it with my GFmx440 too, I would love to see it solved. Not only does 60Hz flicker slightly, optically, in addition my monitor starts giving this very high tone too... arg. I understand that since it is disabled in the hardware, chances are slim for a software override... although I figure the windows driver does just that... I mean if it is possible for windows to set the refresh rates, why can't a MS-DOS utility imitate the windows procedure?

Maybe LCD screens are not that bad after all, since they don't have a refresh rate in that way. but these things will probaly go scaling my pixels? I don't use LCD screens much, I don't know really.

Reply 7 of 7, by RayeR

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I have the same issue on newer nVidia VGAs starting 6600GT, 7300GT and 7600GS. This problem is probably present on 5xxx and all later cards. It doesn't matter who manufactured your VGA card because they mostly use nVidia reference BIOS with slightly modification to timings.

I was talking about it with author of VESA VBEMP driver for WinNT and he told me that nVidia REMOVED some part of VBE code responsible for refresh rate settins so there's no way to cure poor BIOS.

Interesting is that Scitech (before well known its UNIVBE) is now making SNAP SDK - universal graphics drivers for DOS, Win, OS/2 and others. Their SNAP 3.1 nvidia driver IS ABLE TO SET higer refreesh rate on GeForce 6xxx but not on 7xxx and newer (maybe later). But unfortunately SNAP SDK is only driver and API for nevelopers not TSR like UNIVBE was. Then is useless for us. The driver is provided in binary form only so it would be hadr to grab the refresh code but not impossible.
Another way is to do some reverse engineeriing of windows/linux driver to know how they did it. But it will be probably hardware dependent for different chips. It exceed my skills to hacking the drivers but maybe someone else can do it.

Life would be much easier if HW manufacturers will give full documentation to the chips (e.g. like intel do) to let others to write their own drivers/tools instead making some closed windows-only crap. Grrrh!