MongoDB replication throttled due to Mongo using all system memory
I have never seen throttling of replication speed, but I'm working with Linux mongodb machines. I guess that at windows world it can happen, windows OS is throttling when program eats all memory. I remember reading that there are "problems" at windows OS when mongod uses all free memory.

To control how much memory mongod can uses, in Linux, you can use cgroups, so if you use "containers" (docker) in windows, you could control how much resources mongod gets.