Ok First post! I wanted to make sure when I posted it was helpful to this tremendous forum! I built a desktop for audio recording and video these are my specs:
opteron 146 2 ghz
gigabyte motherboard GA-K8NF-9 (Rev 1.x)
1 gig of ram
1 Samsung SATA 200 gig drive
2 Western Digital 80 gig drives
1 Samsung 160 gig drive
Nvidia Evga Pci-e 7300 256 Mb ram (full video acceleration with Titan)
Jas 10.4.8
Tascam US-122 sound card
Now I have been using Osx since 10.4.6 now using Jas 10.4.8 great job by the way Jas!

I have had the same issue all along no matter what I do I get audio stutter when playing back through the usb sound card. I had checked the Kernel I am using Semthex's newest kernel. I then checked that I had installed the proper drivers and sound blaster usb driver to get the sound card to power up and recognize. All where good the sound card had full support. I then checked it on a new intel mac and a pc. The mac had no problems sounded fine playback was great. Now I rebooted to windows and tried playback on my machine and I had a slight audio stutter but only crackles which is usually a sync issue. But this is a problem with my hardware not the interface. So I dug deeper and it so happens that VIA and even TI chip sets have known problems with this particular sound card. So I am going out tonight and buying a pci usb card to get around the VIA chip set and let you know what happens. Has any one ever seen this before and if so have you tried the same solution?
Thanks,
dkudos
EDIT: It was the VIA Chip set bought a SIIG Inc. High Speed USB Dual-Port PCI usb card and all sound works great! VIA Chip sets on gigabyte motherboard GA-K8NF-9 (Rev 1.x) do not work correctly with the Tascam US-122 on windows and Mac OSX. It will cause the audio to pop and click on windows and on OSX it will stutter and drop out.
Please Sticky this or put it in a useful area so others can find it easily.