[lkillen]

First, set up for a WiFi connectioin and see if you are getting the same results. If so, then you know it is not a bandwidth issue.

As far as buffers, each app managers its own. I don't think a Rom change would would make a difference, other than one that is overclocked.

One thing that does matter is available memory. Be sure you have all the apps pushed over to the SD card that you can. Also, test your phone from a vanilla state. I.e. do a beboot and when you start up, immediately run you test. If it performs well but degrades latter on, you know you are dealing with either low memory or overtaxed CPU.