I had just got my HiFiMan 101 and was really stoked about using it.
First let me say that none of this is experience in my wife's laptop nor with my onboard headphone jack.
I first noticed that when my headphones are plugged into the headphone jack (which is a lot louder than the output jack) there was these clicking and scratching noises.
I searched on Google and found some people with similar problems with other amps. One guy on youtube mentioned getting a Clean Box or something. Another commenter stated configuring the BIOS or updating it. There were a slew of things that could be done but none seemed practical or easy.
What I've done:
I noticed a slight drop in noise when I turned off my wireless radios (wifi & bluetooth).
Also holding the amp or moving it slightly further away from the computer made it quieter.
I think if I get an SSD it will help reduce the noise.
Send the HiFiMan back and get another kind of amp. Although I REALLY like the HiFiMan's small footprint. If I do this, which I kinda want to do you think my chances of success in noise reduction will be greater. Portable amp recommendations anyone?
Try connecting the HiFiMan through my firewire port using a firewire to USB cable.