exist-db with Ajax: waiting and receiving times

Question

when doing AJAX calls with XQuery in exist-db I noticed some unusual discrepancies between waiting and receiving times. Usually these are far too small to notice, but recently I ran into a problem.

I need to pass a whole 5 MB response at once and I noticed that while evaluating the call in eXide it takes somewhere below 3 seconds, which is decent since it is a complex call. But when passing it via Ajax I noticed that it takes between 8 and 11 seconds in total, with almost equal waiting and receiving time. Now 5 MB is not really that much, so I was surprised it took so long to transfer it. So I ran the .xql script in an empty browser page, and saw the same issue, 4-5 seconds waiting times and just as much receiving time.

I tried changing the output method to raw text, json, etc but there seems to be no difference whatsoever. Am I missing something and do I need to configure eXist in a certain way to increase these speeds or should I get used that this is just how it's supposed to work for anything over 1 megabyte?