Client acting strange

Hi new here,

So I'm trying to transfer hundreds of files containg bytes of data to a few kb of data. Something is bugging me that when it reaches for example 30kb/30kb, it gets stuck there for a while and the average speed is just getting lower?

Anyone understand what I'm trying to say?
Right, so just found out I've transferred 16,593 out of 115,269 files. Is it because of this?