Confused about these content download times...

Take a look here:

That is before any “optimization” was done. One of the biggest openings for improvement would be to increase the download parallelization of the gallery images. So i found a plugin (shiba media library) that allows you to increase the paralleization by specifying multiple domains (or subdomains) to use. Here are the results:

As you can tell, there is little to no improvement, but only because the content download times seem to increase as i increase the amount of parallelization, thus netting me no return on the change. If you look closely, one image even has a 4704 ms content download time for a 36 kb file!
Is there any reason/cause you guys can think of for this beyond a crappy host? I’m trying to speed up the site for this one guy, but its not going to happen if there is always that single http request bottleneck.[hr]
Is it possible that the host is limiting his total throughput? Currently he is on a level 3 hostgator VPS. Because the more subdomains i add the longer the content download times get.

One thing to also be aware of is that the measurements are done from within the browser so it may be better to consider the “content download time” as “the time it took the browser to read the data”. The reason I make the distinction is that the data is probably coming in quickly enough on the wire but the browser (single threaded and shared with js execution) is just too busy to process the data in a timely fashion.