Here's the whole post, but what it effectively says is that SteamVR is always running it's motion smoothing.
You only can disable it by editing a settings file.
Open this file for the default settings: C:\Program Files (x86)\Steam\steamapps\common\SteamVR\resources\settings\default.vrsettings
Search for the line: "motionSmoothing" : true,
Change the true to false and save the file.
Open the file: C:\Program Files (x86)\Steam\config\steamvr.vrsettings
Go to the section titled: "steamvr" : {
Go to the last line in that section and add a new line with : "motionSmoothing" : false
Add a comma to the end of the previous line and save the file. There should only be no comma on the last line in the section, otherwise you break the file layout.
Seems that it works too.
