My first question is what computers to you have on your farm? In the not too distant past, I had 12 Macs on my farm. As time went on, I started dumping the older machines since they were getting so slow, it wasn't helping at all. In fact, when the fastest clients finished their rendering, the slow ones had a lock on the remaining tasks and just sat their idle. It sped up my Team Renders signigicantly when I just let all the decently fast Macs (Trashcans, iMac Pro and two PCs-i9 and a server-based with two E5 chips.
Those blocks are mostly likely how Corona divides up the image. Each block is a Core or virtual Core trying to render that section. The packets thing you tried only applies to the transfer of the assets across your network. If you have an old network running on T1 or something, that setting can help.