I'm using an AudioFire4 firewire audio interface: Echo Digital Audio Corporation
and this Syba firewire card: Syba - United States

Occasionally the audio cuts out, and I have to reboot to get it working again. This usually happens just after a scheduled backup from my main hard drive to another internal hard drive begins. When it happens, the windows mixer still shows that it is sending audio -- it just isn't making it to the audiofire. Sending S/PDIF to the audiofire still works fine.

I'm guessing that the firewire card is the problem, but I was wondering if anybody had any other ideas before I buy another card.

I've seen that people recommend the TI firewire chipset for audio applications. This firewire card uses the Agere FW323 chipset. Echoaudio says that that chipset is also ok, though: Echo Digital Audio Corporation

If I do buy a new card, I'm thinking this one: PCI FireWire Card - 4 port | PCI 1394a FireWire | 3 External 1 Internal - StarTech.com
Does anyone have opinions on firewire cards? Am I barking up the wrong tree?