OK, note that this is an Engineering sample P4 that will not be sold to consumers. It's a p4 2.8Ghz with HyperThreading enabled. Intel is releasing P4 3Ghz with HT not the 2.8's that I have.
Pipeline: I know you are bummin' on this and have had problems with this machine since day 1. Without having your system here at SF there is no possible way we can get an identical repro of your problems, but please be aware that based on your numerous posts/emails/calls we bought your exact RME card, put it in a P4, and loaded the same OS version(s) as you have- and Vegas works fine in all our tests.
At this point I'd suggest finding somebody someplace in your area with a P4, then load the RME and Vegas and try to repro. I'm not saying there isn't a Vegas issue at the heart of this - but I am saying that it is at least POSSIBLE that your system or config is at fault. If you repro on the second system, please do a system info dump so we can try to find any common factors that might be contributing. If you don't repro on the other system, we'd like to know that too.
Have you physically tried removing the card and moving it into other slots? Have you tried assigning it different IRQ's? I'll be at the AES convention in L.A. this weekend and so will RME....Is there anything you want me to ask those boys for ya?