Sinсe Google Chrome was updated to 50.x version, it become impossible to work with DevTools. This issue reproduced mostly in \"Network\" tab. Every time when you click on \"requ
In my case, I had Local Overrides setup (https://developers.google.com/web/updates/2018/01/devtools#overrides) in Downloads folder which had a lot of files in it and that slowed down devtools.
Setting up overrides in its own seprate directory fixed the slowness.