Thanks, George, you make some good suggestions that I will try... see below for specific answers to your commments... > I have 2 UAD-1's, a Powercore, and use either a Yamaha i88x M-Lan > audio interface, a Digi M-Box Pro, or just use the digital out of my > Mac, and do not see this issue very often. Maybe my MOTU 828MkII is the problem... are any of the interfaces you list above using a Firewire connection? > I have run sessions with as many as 40+ 44.1 24 bit tracks, and a > handful of audio instruments, as well as 20 to 30 audio fx plug-ins, > including 5 or 6 space designers. That is pretty impressive, there is no way I can get that may plug-in instances at the same time without getting Core Overloads regularly. I typically use a mix of 20+ UAD and Logic plugs, and typically 40+ tracks of audio, sometimes with a few tracks of audio instruments. On my G5 dual 2Mhz I am regularly seeing greater than 60% CPU usage, spiking up to +80%. > Do you have a high quality line filter, power regulator, like a Tripplite? Yes, I currently have a Tripplite voltage regulator on my system that seems to work well in filtering most spikes and brownouts. > Have you tried playing audio just from the Mac, to make sure your > audio interface, or one of the cables in your system isn't messing > things up? No, I haven't tried this yet, but I will. This may narrow the problem down to the MOTU interface. > Are you sure you don't have a 3d party plug-in that is causing the > problems? I am not typically using any third party plugs except for UAD-1 plugs. Occasionally I might use something else (e.g. iZotope, Expert Sleepers), but not regularly, and my problem is happening with every song, independent of types of plugs I am using. > ...maybe a hardware problem, like ram, a bad > drive, logic board, or something as simple as a bad usb hub. I do in fact use a USB hub, but it is not connecting any audio related peripherals. But I will disconnect it entirely and see if that has any affect. All my RAM is high quality stuff so I doubt that would be the problem, but who knows. > And please understand I'm saying this with no disrespect meant, really. I know > how frustrating this computer stuff can be. Your suggestions are very much appreciated, I need all the help I can get with this! > Also, make sure you update to the latest UAD-1 drivers. There have > been a couple of issues lately that are being solved with the latest updates. I just noticed UA has a new 4.5.0 driver for the UAD cards so I install it. I also have a few hints from James Ciglar at UA regarding settings that might reduce potential FW / PCI conflicts. FH