Chromedriver is extremely slow on a specific machine using Selenium Grid and .net
I ran into a similar issue where chromedriver was slow in some machines and it turned out to be a proxy issue. Disabling "Automatically detect settings" under Chrome://settings >Change proxy settings> LAN Settings> made webdriver execute commands faster in chrome for me.
My proxy settings were not using automatic detection, but I found the following helped a lot. The time it took to start the driver went down from 43 seconds to 1 second
driver = new ChromeDriver(new ChromeOptions{Proxy = null});