I work in a recording studio where we use mostly MOTU hardware and software. We have been using a PCIe-424 card along with an 896HD and we have a Mac Pro. Lately our 424 hasn't been picking up the 2408 rack units and the 896 has been spiking. We've test both sets of units on other systems where they work fine, anybody out there been having issues with Mac Pros lately?

Check your Audio Bench mark in XBench. I haven't had any issues with the new Intel Macs in a Recording Studio Environment at all (Because I own a recording studio). If need be disable Dashboard and close any other background processes with Activity Monitor.

I wish I could be of more assistance.