GUS came out when people had 386 computers. So it wouldn't surprise me if there are issues on later machines...

Might be related to different BIOS settings for the ISA bus. Try relaxing timings (latency) and change the slow refresh option. There should be a 16 bit I/O recovery time option in the BIOS.
Slowing down ISA bus: recovery time, ISA bus clock

What NMI test are you talking about?
Have you set the used IRQs/DMAs in the BIOS to Legacy ISA ?

NMI is required for the SBOS emulator. For games that support the GUS natively it isn't needed. The NMI test is hidden somewhere in the GUS setup diagnostics tool.

I tried everything mentioned in this thread before changing mobos:

- Tried varying 8bit and 16bit i/o timings, but that didn't make any difference. I usually stick with 4:4 in the BIOS, and that currently works fine on the currrent mobo.
- Tried various CAS timings - didn't make any difference. Current setting of 2 works fine.
- The Award BIOS is pretty similar across these mobos, so I kept a similar config across them.
- IRQs/DMAs set to Legacy ISA in BIOS accordingly.
- NMI test is the last test the installer does. This didn't pass on all BX mobos tested.

I'm not using any emulators like SBOS, just GUS in native mode. It sounds/ works best on the mobo that passed the test - not sure why the others didn't...

As Hal already wrote, NMI is just needed for the SBOS emulation software. For native mode NMI is not required.
So if your GUS does not work correctly in native mode (I usually check with various trackers) then NMI is not the cause.

Still have you checked if any other hardware is using NMI ? (RAM Error Reporting etc.)

Does Megaem loads?

elianda wrote:

As Hal already wrote, NMI is just needed for the SBOS emulation software. For native mode NMI is not required.
So if your GUS does not work correctly in native mode (I usually check with various trackers) then NMI is not the cause.

I haven't installed any trackers yet. For quick testing, I just use the Jukebox found in the Setup for Tyrian 2000; I can quickly change FM/MIDI/GUS/Effects options.

Okay, for native mode NMI is not required, but what is causing the NMI test to fail on the other BX mobos?

elianda wrote:

Still have you checked if any other hardware is using NMI ? (RAM Error Reporting etc.)

Does Megaem loads?

On the working system, there's just the GUS and an S3 GX2 installed. Most things are disabled in the BIOS. It's a P2 400Mhz, downclocked to 133Mhz, running Win98SE. No errors are being reported. When I run the GUS emulators:

1) SBOS initialises (v3.82), tested on Doom2, and Tyrian2k Jukebox.
2) UltraMax SBOS inistialises (v0.21 beta), tested on Doom2, and Tyrian2k Jukebox.
3) MegaEm fails (v2.07) - reports EMM incompatibility, cannot expand server page directory (probably the EMM version in Win98SE)...?