I'm going to guess your picking up some nice red spikes in there when the drop outs happen, if so try disabling you lan/wifi and see if it improves.
The problem tends to be to save cash they tend to use combo controller chips for all the I/O and these don't tend to play nicely where real time audio recording is required. All you can do really is run the test see if it spikes and then start killing devices & services to see if each one being turned off helps or not.
Can I ask why you went for this as a solution rather than a decent two channel field recorder?
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