Firewire problem, crashed video/sound

Hello all. This is a weird issue and hopefully has a fix to it. Here's the scoop: I bought a Focusrite Saffire LE audio device that runs on a 6 pin fire wire. About 5 minutes into using it, the sound would stop and a high pitched tone would come out (like 15,000 Hz or up) my speakers. I also noticed that no media players would work: Sound players wouldn't even try to play and video players would go about 2 frames and stop w/ on sound. I worked with tech support and after tweaking PCI latencies, I got the system stable. To note, I used the latency timing device from PCI Latency Tool in conjunction with the latency adjuster included with the Saffire stuff (this one is used for sound buffering i.e. ms timings). I'm doing another motion capture project now that uses video. This takes Analog to Digital via the Dazzle hollywood DV-Bridge (Also firewire). I've been testing only video right now but my video and sound keep crashing, except for the camera feed inside of Max/MSP Jitter (the prog I'm using to do motion capture). I've been trying to fiddle with the PCI Latencies but I don't know which way to move them. Because it seems like a sound card issue, should I bump up the sound a bunch? Or could it be something with the firewire not getting enough latency? Or is it something with the bridges (PCI or ISA)? One thing of note, Before I installed all this hardware and did these projects, I had to pretty much build a new computer after my old motherboard died and got some weird errors during installations. The system is stable except for the sound problem with a firewire device inserted. I'd love to do a wipe and fresh install but my BFA thesis is due in less than a week. Any help on this would be greatly appreciated. Thanks

I don't know the solution but for others reading, some more information would be helpful. What version of Windows? What motherboard? How much RAM? What graphics card? I do know, IIRC, that PCI latencies are typically set to a multiple of 8, often between the range of 32 and 248 (I don't know why 248 and not 256, but that's what I have seen). I also know that graphics card makers try to ensure their cards do not suffer from stuttering problems so they set the latencies high - to 248 higher than needed. On some systems, this effectively chokes other PCI devices, such as sound and to some extent, network interfaces too. You might just use the trial and error method to find the best stutter free settings, starting by lowering the video card's latency to something under 100 and see what happens. Good luck and keep us posted.

Yes, I have tried lowering other devices to 32 while keeping the firewire and audio card at 128. This didn't really help either. And yes, sorry for the lack of info. Windows XP SP2 most up to date 2 ATI 2600 Crossfires MB ECS KA3 MVP (V1.0A) 580X CS AM2 CPU AMD|A64 X2 5400+ 2.8G AM2 1M % 4x1G rams set for Dual Channel That is a keen observation about the graphics cards though. Perhaps I'll look more into it. I do have the cards clocked high (or at least optimized through ATI's own GUI interface), so perhaps they are hogging. I may be able to get a whole other computer for this project so it might not be a problem anyway. I'll let y'all know what I find.