It happens with my Mac mini and Macbook Pro via firewire to the Weiss.
Anything above 24/96 is plagued by digital noise if other programs are running.
Norm
Do not skimp on the RAM. I have a DAC2 and a new Mac mini with 4GB RAM and cannot play 24/176 files if ANY other application or utility is open. All other files up to 24/96 play flawlessly.
Norm