I've got a Newer Technology 1.8GHz 7448 G4 CPU installed in my PowerMac Digital Audio. So far after a few months use, it seems to work flawlessly in 10.4.11 Tiger and from the testing I've done with Leopard, it seems to work OK there too (my GPU is limiting me there, though). In any case, it DOES work with OS9 as advertised. However, I only get sound in OS9 on the first boot into it after an NVRam update (you have to update your NVram with a patch each for booting into OSX and OS9 after you install the firmware patches so the CPU will work in general). In other words, after the first boot I had sound. When I rebooted into OS9 again, I lost my sound (only for OS9). The only way I could find to get sound back in OS9 was to reset NVram and then reinstall the OS9 boot patch. I'd then get working sound the next time I booted into OS9. But when I rebooted, sure enough sound stopped working again (and so on; the cycle is perfectly repeatable). OS9 doesn't report any problems with the sound. I simply do not get any output after the first run. Does anyone have any idea of what might be happening that I'm losing sound? Frankly, I don't even recall if there was any sound issue with OS9 before I installed the CPU upgrade, although I don't recall one (I hadn't run a lot of sound using apps in OS9 at that point; in fact I hadn't really played with it a whole lot at that point). None of this is any kind of emergency; I'm just playing around with OS9 (seeing as I came from Windows/Linux and then Amiga before that and never got to play with any classic MacOS save the occasional school app), but I would like sound in it when I'm playing with OS9. I've sent a bug report to NewerTech, but I'm not sure how much they'd bother to look into an OS9 sound issue given its age, etc. But I thought maybe there might be an OS9 expert on here that would have an idea. Given the NVRam patch gets it working again, I'm of course thinking something in NVRam is getting screwed up along the way, but I have no idea what.