It's a Gateway JAZZ16-MV16 I believe. It works admirably in most scenarios but it has an exceeding amount of "popping" during MIDI playback at any volume level. It's specifically popping when notes are played, I don't believe it's random background noise or non-opl channel noise.

Is this a common problem with this card? Any idea what might be up?

I'm using a 5x86/P75 on a Viper 808 single board computer as my processor and motherboard, with a no-name ISA backplane.