Crazy problem: USB port provides bad sound, but only at low CPU usage, Was: CrazyProblem:BadSound@lowCPU-usage (Please use your space bar.) Options

[reselty]

Hello
USB port provides poor sound quality

It’s a Windows XP or Hardware not a DJ-Soft Problem.
Only I do not know, where I could ask such a question otherwise.

Problem occurs when sound output via USB (via Jack OK).
- Via ext USB Sound Card
- Via USB Headphone / Mic earphones (which have a well-integrated sound card)

No Problem when:
+ powered USB hub between PC and sound card "sound OK" ( "bad sound" without power )
+ The REALLY WEIRD: if I increase CPU usage, e.g. if I move a window in Windows continuously the output is OK

Attachment: 2 WAV sound files:
http://dl.dropbox.com/u/39224041/USB-out-WAV%27s.zip
I'm alternating every 10 seconds during playback,
- move a window in a circle permanently CPU Usage 60..64% >> Sound ok
- Then without window moving CPU Usage 2...7% >> sound bad
Each WAV starting with window moving(so: 10s good, 10s bad, and so on (etc))

Could it be due to the USB power? (Not yet measured)
I've read that some USB devices could damage PC.
"This could, in extreme cases damage the USB port on the host or upset the energy management of the computer, which can lead to unstable behavior."
Possible? While yes: enough to measure only via Soft-PC-Diagn.Tool e.g. SpeedFan? Or do I have to measure with a MultiMeter?

Could it be speed of USB?
My PC has USB2.0, however I have not found out about whether "Hi-Speed" or "Full Speed"

What ever could it be???

Am glad to rest every tip, even to the other proposals in which forum should be posted!
Thank you
Reselty

[Ouroboros]

It seems illogical that it should work better at high CPU loads, but try checking the DPC latency.

http://www.thesycon.de/deu/latency_check.shtml