Disruptor wrote on 2025-04-21, 10:36:

byte_76 wrote on 2025-04-21, 10:28:

Okay I tested in my GA-5486AL and it just beeps 🙁

Which FSB?

I have it set on 40MHz which gives me 160MHz with my Am5x86 P75.

byte_76 wrote on 2025-04-21, 11:52:

Disruptor wrote on 2025-04-21, 10:36:

byte_76 wrote on 2025-04-21, 10:28:

Okay I tested in my GA-5486AL and it just beeps 🙁

Which FSB?

I have it set on 40MHz which gives me 160MHz with my Am5x86 P75.

Did you add a heatsink to the PCI-AGP bridge chip?
Perhaps the AGP bridge is fried because it got too hot.

perphaps the bios isn't initializing the card due to it being behind an agp-pci bridge.

weedeewee wrote on 2025-04-21, 12:16:

perphaps the bios isn't initializing the card due to it being behind an agp-pci bridge.

That also may be possible.
Please note that my HOT-433 does NOT show the graphics card in PCI devices list because it is on bus 1. But it is initialized properly with a BIOS patched by vogons user mkarcher.

The card still works fine in a slot 1 machine.

Yes, if the bios needs to be patched on the 486 board then that would be the reason.
I’ve not patched anything.

byte_76 wrote on 2025-04-21, 11:52:

Disruptor wrote on 2025-04-21, 10:36:

byte_76 wrote on 2025-04-21, 10:28:

Okay I tested in my GA-5486AL and it just beeps 🙁

Which FSB?

I have it set on 40MHz which gives me 160MHz with my Am5x86 P75.

I've used one with benchmarks on an m919, with a cyrix at 2x60. It does not like to initialize on a 40mhz bus. It also wont work on a halved 40mhz (2omhz) bus. You have to either do the "switch bus speed on the fly -from 33 to 40", or, have as mentioned a patched bios that slows down the sequence (sorry if I got that wrong, but pretty sure that's how that fix worked).

I couldn't get it to work under windows 98 on that system though, BSOD after driver install and restart. I did not try an AMD 5x86, I'm guessing that wouldn't help as the problem is likely lack of non Pentium cpu support in the drivers. The g400 has only one version of driver that will work on a 486 but unfortunately there is no such one for the 450.

The G450PCI is notoriously difficult to work with in an FSB40 system, so I highly recommend to downclock the system to 133MHz first. The HiNT/PLX chip used for PCI/AGP "translation" does not work reliably at 20MHz PCI clock, and it also overheats when running at 40MHz PCI clock without a heatsink. The documentation for your board does not indicate whether you can set up a configuration with 40MHz FSB and 40MHz PCI, but possibly you get that when you JP7-JP9 for 40MHz but leave JP10 open.

I strongly suggest you go down to 133MHz (4*33) and if you got the card working at that setting, you can try to find a way to get 160MHz @ PCI40.

HiNT/PLX chip used for PCI/AGP "translation"

It's a PCI-PCI bridge chip. All AGP cards work as PCI cards by default anyway.

mkarcher wrote on 2025-04-21, 20:48:

The G450PCI is notoriously difficult to work with in an FSB40 system, so I highly recommend to downclock the system to 133MHz first. The HiNT/PLX chip used for PCI/AGP "translation" does not work reliably at 20MHz PCI clock, and it also overheats when running at 40MHz PCI clock without a heatsink. The documentation for your board does not indicate whether you can set up a configuration with 40MHz FSB and 40MHz PCI, but possibly you get that when you JP7-JP9 for 40MHz but leave JP10 open.

I strongly suggest you go down to 133MHz (4*33) and if you got the card working at that setting, you can try to find a way to get 160MHz @ PCI40.

Thanks for the info.

At 40MHz bus with an S3 Trio 64 and the PCI 1/2 divider JP10 closed, the system posts and works fine. (Ie. PCI clocked at 20MHz)

With the same config and the Matrox installed, it just beeps. So the Matrox doesn’t even work with PCI at 20MHz.

With the S3 Trio installed and the bus at 40MHz, but with the PCI 1/2 divider JP10 open, it just beeps exactly as it does with the Matrox. (So the S3 does not work at 40MHz)

I did not complete the testing, so the next step will be to lower the bus back to 33MHz as suggested without the PCI divider and then test the Matrox again.

The Serpent Rider wrote on 2025-04-22, 06:37:

HiNT/PLX chip used for PCI/AGP "translation"

It's a PCI-PCI bridge chip. All AGP cards work as PCI cards by default anyway.

Yes, correct, the datasheet says it’s a PCI-to-PCI bridge and that the specific version on the Matrox card is designed to work at 33MHz.

https://www.digchip.com/datasheets/parts/data … -CC33BC-pdf.php

This might be why the system won’t POST with any other bus.

Okay, I've tested the Matrox with my board set to 33MHz bus and no PCI divider.
The system beeps once as if everything is normal but I don't get any video output from the card on either the VGA or DVI ports. (so the monitor LED remains orange)

So at this stage, and disappointingly, the Matrox is unfortunately not a viable option for my 486 machine.

Maybe it just needs the BIOS patch?

byte_76 wrote on 2025-04-22, 16:17:

Okay, I've tested the Matrox with my board set to 33MHz bus and no PCI divider.
The system beeps once as if everything is normal but I don't get any video output from the card on either the VGA or DVI ports. (so the monitor LED remains orange)

Has it worked in another computer, and what kind of computer has this been?

byte_76 wrote on 2025-04-22, 16:17:

So at this stage, and disappointingly, the Matrox is unfortunately not a viable option for my 486 machine.

Maybe it just needs the BIOS patch?

Possibly a BIOS patch will help. I have no experience with the PCI implementation in the AMI WinBIOS (which I assume to be on your board, as the manual show WinBIOS screenshots). I also have no experience with FinALI chipset of your board, so I don't know whether the non-synchronisation is a BIOS problem or a hardware problem in your 486 board. The BIOS is obviously able to somehow recognize the graphics card behind the PCI/PCI bridge, as you would get a beep code if no graphics card is installed. I'm personally out of suggestions.

byte_76 wrote on 2025-04-22, 07:10:

Yes, correct, the datasheet says it’s a PCI-to-PCI bridge and that the specific version on the Matrox card is designed to work a […]
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The Serpent Rider wrote on 2025-04-22, 06:37:

HiNT/PLX chip used for PCI/AGP "translation"

It's a PCI-PCI bridge chip. All AGP cards work as PCI cards by default anyway.

Yes, correct, the datasheet says it’s a PCI-to-PCI bridge and that the specific version on the Matrox card is designed to work at 33MHz.

https://www.digchip.com/datasheets/parts/data … -CC33BC-pdf.php

This might be why the system won’t POST with any other bus.

Additionally, after Reset the G450 derives all clocks from the PCI clock and there are additional constraints on these clocks. As I dont See why underclocking the Bridge should be an issue, it might help patching the bios to instead use PLL generated clocks from the beginning.

I can use my Amiga driver for the G450 to provide validated pll settings for generating 33mhz via the MGA System PLL instead of pci if anybody wants to Patch the BIOS accordingly.

My board has an Award BIOS. (GA-5486AL)
It looks like the typical interface with the blue background.

https://theretroweb.com/motherboards/s/gigabyte-ga-5486al

I have tested my Matrox G450 in my Asus P3B-F slot 1 machine and it works fine.

What is the best Windows XP driver for this card to properly support D3D and OGL?