Hello, I dont know if you resolved this. But i had the same problem. only my hiccup was slightly less severe. For me the stagger would really annoy me when playing audio. it would sputter just as you described.
I was able to resolve my issue in part. Meaning i dont know what the cause but i have a suspect. and have greatly reduce the problem to a rare event.
I personally think it's the Seagate hard drives. i upgraded to 2x 500gb HDs in my laptop. and noticed this problem not long after. However i cannot say for sure this is the problem because my fix was not to remove the HD's.
Here are my suggestions as this is what i did.
First go to Device manager and Remove your display driver (delete) let the basic VGA driver install. see if that helps. THen do this one by one with all drivers you can. and see if your problem continues.
Next try a clean install with one harddrive, see if the problem persists.
For me, i removed one of my harddrives, did clean install, and then added the second drive later after system was up and stable. The Problem is mostly gone with a rare occasional "Hiccup" when downloading a large file.
So in my case, it could have been either the HardDrive or the Network card sharing interups.
But if you think about it, it would make sense that it's the HardDrive.
When the system needs to spin up the HD and transfer data, this is tying up the bus, do to some error. When i reinstalled, the HD controller is now acting right and not hogging the Bus. atlest this is my thinking.