danieljm wrote on 2025-02-23, 18:47:

I've got a Gravis Ultrasound rev. 2.4 that I'm trying to get running on a PCChips M912-based system(UMC chipset) and it's workin […]
Show full quote

I've got a Gravis Ultrasound rev. 2.4 that I'm trying to get running on a PCChips M912-based system(UMC chipset) and it's working inconsistently between different games.

Jazz Jackrabbit - Works great
Dark Forces - Works great
Descent - Music works, but no SFX
Duke 3d - SFX works, but no music
Doom - No sound at all

Does this make sense to anyone?

I put the GUS in a 440BX system and all games worked fine, but that also means that everything else changed in the system as well. So I tried another 486 board(ALi chipset), transplanting all the parts from the M912 system and it's a lot better, but the SFX in Descent and Doom are a little clipped or distorted.

The other parts in the system are as follows:
Am5x86-133
16MB FPM RAM
Trident VLB video card
Promise VLB controller
3Com NIC for XT-IDE ROM only, no drivers loaded

I'd love some help because I really can't make any sense of it.

Is the ISA bus clock on the 486 boards running at more than 8.33MHz or so ?

darry wrote on 2025-02-23, 19:44:

danieljm wrote on 2025-02-23, 18:47:

I've got a Gravis Ultrasound rev. 2.4 that I'm trying to get running on a PCChips M912-based system(UMC chipset) and it's workin […]
Show full quote

I've got a Gravis Ultrasound rev. 2.4 that I'm trying to get running on a PCChips M912-based system(UMC chipset) and it's working inconsistently between different games.

Jazz Jackrabbit - Works great
Dark Forces - Works great
Descent - Music works, but no SFX
Duke 3d - SFX works, but no music
Doom - No sound at all

Does this make sense to anyone?

I put the GUS in a 440BX system and all games worked fine, but that also means that everything else changed in the system as well. So I tried another 486 board(ALi chipset), transplanting all the parts from the M912 system and it's a lot better, but the SFX in Descent and Doom are a little clipped or distorted.

The other parts in the system are as follows:
Am5x86-133
16MB FPM RAM
Trident VLB video card
Promise VLB controller
3Com NIC for XT-IDE ROM only, no drivers loaded

I'd love some help because I really can't make any sense of it.

Is the ISA bus clock on the 486 boards running at more than 8.33MHz or so ?

Thanks for the reply. Yes, I did check that. The M912 had been running at around 10 MHz, but I changed it back to standard with no effect. So all 3 boards I tried were checked and were running at 8.3 MHz with the observations mentioned above.

Whats are the GUS's and 3Com's configs?