Recently the hiccups that happen when playing hich bitrate audio (happens in 320 kbps and not in 192) and videos (HD) started to really annoy me so I came here.
I have windows 7, intel i7 870 processor, roland UA-4FX USB sound card, radeon hd5800 graphics card, and 4gb ram, I think all of them have up to date drivers.
The clicking intensifies when doing rather CPU-heavy things like opening microsoft word but it is always there in high bitrate files, but the CPU load never goes above 20% in task manager.
The hiccups are such that audio playback stops for a very short time periodically and making a click sound as if you removed the cable of the speaker.
USB is your bottleneck, USB is not as fast as advertised and I would never use something as integral as sound as an external application. See if Roland has startup software that creates equalizer software. Run it as normal with no changes. Anytime you re-install Video/Audio drivers, always run your DirectX setup right after, not Diagnostics, SETUP.