I purchased 2 ART Tubefire (TF) a few months ago to facilitate recording live gigs, needed more than 8 channels is the reason for 2 units. I am using a P4 3.0ghz, 120gb sata (dedicated drive), 2gb dual memory, firewire (VIA chip) pci card equipped PC running Windows XP SP3. When recording with just 1 Tubefire (8 ch) I have absolutely no problems whatsoever, all is perfect. But when I connect in the 2nd TF unit via the firewire connector (either thru the TF expansion port, or the 2nd port on the PC firewire card) I get sync problems (noise/static) occuring between the two units. ART says they have tested the PC config with no problems using a TI chip firewire card, they say the VIA chip firewire card should be OK as well. Checking my PC stats shows no problems with proc or memory constraints. I have tested this config on a borrowed MacBook (1.8mhz, 500mb ram) with no problems. I have added a wordclock cable between the unit, with a terminator...no change. Do I need to use a Wordclock source? Is there some Windows registry setting that requires a tweak? Any suggestions?