In general, FireWire interfaces and the OS support in Windows was designed well before modern CPUs and their aggressive power management started. Furthermore, the IIDC DCAM spec chose to use Isochronous transfer modes for image streaming, meaning they are extremely sensitive to real-time DMA performance. The buffers on most FireWire cards are so small that they can only hold a packet or two worth of data. The interval between packets is so short that if the CPU goes into a lower-power mode for even a few milliseconds (which they tend to do now) you can have data dropped.
The couple of recommendations are:
-Try seeing if you can put a different 1394 card in. I've found the TI 1394b ones tend to work best.
-Keep trying all the different steps listed in the PGR document to disable all power management functionality.
-Try lowering the packet size. These will be better on the small FIFOs of the 1394 chipset. It sounds like your program is overriding the settings saved by MAX, so this might not help unless you have access to the source code of the app.
