I started streaming with a general use PC laptop, then went to stock Mac Mini, this setup to be used solely as streamer, therefore max services disabled, this was easily heard improvement over the laptop. Next was a newer generation mini, this one modded with Core Technologies LPS, now this was big improvement over the stock mini. Next was a newer yet generation mini, this one maxed out with fastest processor, most RAM, dual hard drive setup, OS on separate drive, Uptone MMK with Uptone JS-2 lps, again better than previous mini. Now I use custom build Windows/ATX board based streamer, this build all out along lines of Taiko, again much improvement over my most extreme mini.
Bottom line, stock computers leave much to be desired as audiophile streamers. They are noisy devices, even laptops with battery power, they may work as convenience streamers, but don't belong as audiophile source. Treat streaming with same care as vinyl source, anything less isn't a first class source.