As you know I run a beta of the most current version of High Sierra 10.13.3. This update for High Sierra is due to be released soon so be looking for it. Supposedly, the 10.13.3 update contains an improved solution for the recent Spectre CPU flaw from Intel which affects all Macs. The knock about the Spectre fix is it is supposed to slow down your computer. I am running 10.13.3 Beta 5 and I can tell you this install is not slowed down in any way that I can perceive. It is very snappy, downright fast. This may not be the case on PC’s, but as far as my Mac is concerned, there is no slow down perceptible.