1920*1080@144hz

Not possible. That's more bandwidth than 2560x1600@60Hz, which is a limit for DVI Dual link. Then again, why do you need full 1080p resolution for Windows 98? Most games of that era can't work properly with formats wider than 4:3. 1440x1080 is within spec.

Something is clearly wrong here...

https://en.wikipedia.org/wiki/Digital_Visual_ … ace#cite_note-6

Example display modes (dual link):
QXGA (2048 × 1536) @ 72 Hz with CVT blanking (2 × 163 MHz)
HDTV (1920 × 1080) @ 144 Hz[6]

https://zowie.benq.com/ru-ru/support/faqlist/ … ing/faq049.html

Note: Only DVI Dual Link supports 144Hz on the XL2411.

In the first message, I indicated that when a modern video card is connected, DVI Dual-Link works in full. That is 1920*1080@144hz. And on the 7950GT there is no signal at all, regardless of the resolution and frequency (Black screen from the moment the PC is turned on until the desktop). Any signal. To understand why it does not work at all, for starters. At least somehow it would work...

So you still need some kind of special monitor, with full support for DVI Dual-Link, 144Hz and GeForce 7950GT at the same time? What then is its peculiarity and difference from any modern monitor with DVI Dual-Link? How to immediately understand whether a particular monitor supports 7950GT via Dual-Link or does not support it? I thought that DVI Dual-Link is also in Africa Dual-Link, but it turned out that here, too, there is a rake in terms of using it with old hardware. Only manufacturers indicate this somewhere? And how in this case to figure out how to find the right monitor? If this is indeed the problem, of course. So far this is just a guess.

The Serpent Rider wrote on 2022-10-25, 15:06:

1920*1080@144hz

Not possible. That's more bandwidth than 2560x1600@60Hz, which is a limit for DVI Dual link. Then again, why do you need full 1080p resolution for Windows 98? Most games of that era can't work properly with formats wider than 4:3. 1440x1080 is within spec.

https://web.archive.org/web/20060219163557/ht … /lib/dvi_10.pdf

Dual link DVI can handle 330MHz (possibly more, but the doc is more than a bit ambiguous on that).
1920x1080@144Hz is definitely doable within 330MHz at least with custom reduced blanking .

DoZator wrote on 2022-10-25, 16:22:

So you still need some kind of special monitor, with full support for DVI Dual-Link, 144Hz and GeForce 7950GT at the same time? What then is its peculiarity and difference from any modern monitor with DVI Dual-Link? How to immediately understand whether a particular monitor supports 7950GT via Dual-Link or does not support it? I thought that DVI Dual-Link is also in Africa Dual-Link, but it turned out that here, too, there is a rake in terms of using it with old hardware. Only manufacturers indicate this somewhere? And how in this case to figure out how to find the right monitor? If this is indeed the problem, of course. So far this is just a guess.

There might well be some kind of bug or limitation in your 7950GT's BIOS EDID handling .

I suggest you try the following.

a) Boot the 7950GT with a working DVI single link monitor
b) without shutting down, disconnect the monitor and connect the Zowie 144Hz one

Do you have an image then ?

darry wrote on 2022-10-25, 16:26:

There might well be some kind of bug or limitation in your 7950GT's BIOS EDID handling . […]
Show full quote

DoZator wrote on 2022-10-25, 16:22:

So you still need some kind of special monitor, with full support for DVI Dual-Link, 144Hz and GeForce 7950GT at the same time? What then is its peculiarity and difference from any modern monitor with DVI Dual-Link? How to immediately understand whether a particular monitor supports 7950GT via Dual-Link or does not support it? I thought that DVI Dual-Link is also in Africa Dual-Link, but it turned out that here, too, there is a rake in terms of using it with old hardware. Only manufacturers indicate this somewhere? And how in this case to figure out how to find the right monitor? If this is indeed the problem, of course. So far this is just a guess.

There might well be some kind of bug or limitation in your 7950GT's BIOS EDID handling .

I suggest you try the following.

a) Boot the 7950GT with a working DVI single link monitor
b) without shutting down, disconnect the monitor and connect the Zowie 144Hz one

Do you have an image then ?

There is. But only low resolutions. When set to high, writes - out of range.

I also managed to set 1920x1080, but only 60hz. And after rebooting the PC again, a black screen from the very beginning and - no signal.

In the first message, I indicated that when a modern video card is connected, DVI Dual-Link works in full. That is 1920*1080@144hz.

AFAIK Nvidia DVI connector of that era can handle 2048x1536@85Hz or anything that can fit into that bandwidth range (2560x1600@60 as mentioned above), but no more than that.

The Serpent Rider wrote on 2022-10-25, 17:06:

In the first message, I indicated that when a modern video card is connected, DVI Dual-Link works in full. That is 1920*1080@144hz.

AFAIK Nvidia DVI connector of that era can handle 2048x1536@85Hz or anything that can fit into that bandwidth range (2560x1600@60 as mentioned above), but no more than that.

That 2560x1600@60 limitation over dual-link DVI is often mentioned in DOCs [1] and ads, but detailed exact timings are not mentioned (at least I haven't seen them), but I'm guessing at CVT-RB, so maybe 268MHz or so as calculated by [2] .

Maybe the TMDS and accompanying logic in the the 7950GT (and other similar GPUs) are either limited to 268-ish MHz and/or aren't flexible enough to handle what would have been, at the time, oddball timings like 1920x1080@144Hz .

OP could try setting up custom resolutions/timings with reduced blanking to test (trial and error) how far things can be taken. This is assuming the Nvidia drivers of the time allow this or that a third party tool like Powerstrip is used .

EDIT : Maybe the old Nvidia driver is trying to push wacky timings with huge blanking intervals that exceed even 330MHz by default .

[1]
https://www.evga.com/products/specs/gpu.aspx? … 6D-E9455529E242

[2]
https://tomverbeure.github.io/video_timings_calculator

To try this, as far as I understand, you must first somehow switch to Dual-Link mode? Using your method, the card continues to work apparently in SingleLink mode, because at 1920x1080 more than 60hz can not be set.

darry wrote on 2022-10-25, 18:15:

Maybe the old Nvidia driver is trying to push wacky timings with huge blanking intervals that exceed even 330MHz by default .

This is also possible, but the problem starts earlier - a black screen immediately after turning on the PC, even at the boot stage. Which confirms your assumption about the absence of the necessary BIOS EDID information in the video card. Or even in the monitor itself.

DoZator wrote on 2022-10-25, 18:24:

To try this, as far as I understand, you must first somehow switch to Dual-Link mode? Using your method, the card continues to work apparently in SingleLink mode, because at 1920x1080 more than 60hz can not be set.

I don't know how the dual-link ability detection logic is supposed to work nor what triggers it and when. I would have presumed that hot-plugging a dual-link capable monitor to a running system would enable dual-link to work, but that's just a guess as to how it would be supposed to work. And even if my guess is correct, that doesn't mean there isn't a bug here preventing it from working .

Another point to consider is that your card might have a defect/design flaw preventing dual-link from engaging at all.

Or maybe dual-link engages only if needed according to driver or BIOS logic .

As a test, what happens if do the monitor switcheroo at boot to get it working with an image and then try to switch to 1920x1080@70Hz or 75Hz or even 100Hz ? That is nominally beyond single link capability.

Also, does the Nvidia driver allow you to set timing type CVT, CVT-RB , DMT , etc ?

DoZator wrote on 2022-10-25, 18:37:

darry wrote on 2022-10-25, 18:15:

Maybe the old Nvidia driver is trying to push wacky timings with huge blanking intervals that exceed even 330MHz by default .

This is also possible, but the problem starts earlier - a black screen immediately after turning on the PC, even at the boot stage. Which confirms your assumption about the absence of the necessary BIOS EDID information in the video card. Or even in the monitor itself.

That's not necessarily a big problem, as it could be overcome with an EDID emulator (are there ones with dual-link passthrough support, or otherwise need to modify build your own) or maybe a dual-link to DP converter with a programmable EDID.

EDIT : If you've got spare cash and time, this might be worth a try https://www.amazon.com/Gefen-GTV-DVIDL-2-MDP- … r/dp/B01LZT2Z15 . According to some reviews, it is more flexible than official specs let on, but still might not help at all, depending on what is actually causing the issue in your case .

I did not rule out a card defect in the very first place, and it was for this reason that I tried several similar cards from different manufacturers (All on GPU G71 \ G70). And everywhere the observable behavior is the same. This possibility, however, cannot be ruled out since there is no guarantee that all tested cards are free of defects. But it doesn't look very much like it.

The rest I'll check and see. Thank you.

As for the EDID, is it possible to update it in the graphics card's BIOS?

DoZator wrote on 2022-10-25, 18:57:

I did not rule out a card defect in the very first place, and it was for this reason that I tried several similar cards from different manufacturers (All on GPU G71 \ G70). And everywhere the observable behavior is the same. This possibility, however, cannot be ruled out since there is no guarantee that all tested cards are free of defects. But it doesn't look very much like it.

The rest I'll check and see. Thank you.

As for the EDID, is it possible to update it in the graphics card's BIOS?

The EDID is in the monitor . It can sometimes be updated over DVI or HDMI. This ability is monitor dependant.

Last time I tried GF 7950 GT, it was able to run 2560x1440 over DVI - so definitely using dual-link. However it was using windows7 and latest driver. I have no idea how windows98 would behave.

I tried it in Windows XP SP2 with 306.81 driver and DVI Dual-Link worked. Now it looks like this: from the moment the PC is turned on until the desktop appears, there is a black screen, no signal. As soon as the Windows XP startup sound is played, the image appears. I managed to set it to 1920x1080@120Hz now. It turns out that the matter is not only in EDID, but also in the driver. There was no image with the old driver in Windows XP. Now it is. For Windows 98 there are only old drivers and the newest one I know of is 82.69.

darry wrote on 2022-10-25, 18:38:

As a test, what happens if do

the monitor switcheroo at boot to get it working with an image and then try to switch to

1920x1080@70Hz or 75Hz or even 100Hz ?

I tried switching to DVI during the multiboot menu. The image appeared and was present

throughout the boot of Windows 98. However, when entering the desktop, again a black screen

- no signal.

Thus, switching on the fly only works under Windows.

darry wrote on 2022-10-25, 18:38:

Also, does the Nvidia driver

allow you to set timing type CVT, CVT-RB , DMT , etc ?

Allows.

darry wrote on 2022-10-25, 19:48:

The EDID is in the monitor . It

can sometimes be updated over DVI or HDMI. This ability is monitor dependant.

Is it necessary to add the necessary information about the GeForce 7950GT to this EDID, which is in the monitor, by updating or flashing, so that the monitor understands the DVI signal issued by it immediately after turning on the PC (and not after a kick from the driver)?

The fact is that the driver for Windows 98 is too old and, apparently, without modifications, at least it cannot "kick" modern monitors. Even in Windows XP, you had to install the 300 series driver for this. Only with it the monitor began to understand the signal from the GeForce 7950 GT.

I have not yet looked for an edge driver, starting from which, image transfer becomes possible. It would be necessary to find the very first such driver in order to try to understand how this happens and whether this functionality can be transferred to another driver (Eventually to ForceWare 77.72 and 82.69 for Win9x drivers), so that Windows 98 can be used with modern monitors via DVI dual link.

And in general, are there any (120\144)hz monitors that already support the GeForce 7950GT under Windows 98 out of the box, via a DVI Dual-Link connection? If they exist, is it probably easier to find such a monitor and not suffer with these drivers? After all, this problem hardly existed during the release of the GeForce 7950GT. After all, the first LCD monitors with support for DVI Dual-Link and 120hz + already existed around that time, which means that the drivers of that time already supported this function. Simply, for some reason not yet clarified, they are not compatible with modern monitors. In any case, this is how I understand the phenomena observed here.

The EDID contains information about what the monitor supports, not information about any specific video card .

On issue I have seen in the past is an old video card's vBIOS trying to output a resolution (with specific timings) that was outside the capabilities of the video card, i.e. 1920x1200@70Hz , because that is what the monitor's EDID said was its native resolution . This was remedied by using an in-line EDID emulator with a custom EDID that spoofs a resolution (and timings) that the video card can actually handle .

IMHO, unless you really insist on trying to run >60Hz at 1920x1080 in Windows 9x, I would just get an EDID emulator that you can program to expose 1920x1080@60Hz as a native resolution or simply use another monitor that actually has that native resolution .