So I've got this 440EX board with a Celeron 300A now. I tested the board initially with a Celeron 266 and the GUS was running fine. I was super happy that High DMA was working and MegaEM could use NMI.

But now I'm running into problems with crackles in the sound:

- Duke Nukem 3D (1.3D and 1.5) have crackles with sound effects and Stalker is a tiny bit corrupted in 1.3D;
- Transport Tycoon Deluxe plays all sound effects in one go when the first effect should be heard;
- Tyrian 2000 has crackles with sound effects;
- Rise of the Triad has crackles with sound effects;
- Warcraft has done this only once;

But:
- Doom has no issues;
- Demoscene productions have no issues;
- Quake has no issues;
- PlayMIDI has no issues, load1024 works fine;
- Nascar racing demo has no issues;
- Warcraft 2 Demo has no issues.

It seems to me that the issue is slowly getting worse the longer I'm testing. Also Duke Nukem 3D and Transport Tycoon Deluxe are starting to hang often, even getting a "Can not close file" message with Duke at one point. I did a new install on a Industrial Grade CF disk I've used in my previous system when I got that error.

I've tried:
- Two other CF disk (need to try a HDD);
- Promise SATA controller instead of on-board IDE;
- I/O recovery settings;
- Passive release enable/disable;
- Delayed transaction enable/disable;
- L1 and L2 cache on/off;
- Both downloaded drivers and the original floppies for the GUS installation;
- High DMA / low DMA;
- Disabled all serial/parallel ports;
- Slowest RAM options.

I plan to swap out the CPU, drive and the RAM to see if that helps. But does anybody recognize this? The combination of crackling sound and the games that crackle being unstable makes it hard to pinpoint. I will test the card in another system when I have time.