Performance on Vive below 10FPS on a 1080

Hi. Recently (I don’t know the event that triggered this behavior) I get over 100ms on the draw thread and gpu thread when I turn on VR.
This pernicious behavior happens on several versions of the engine (4.13 official, 4.11 official, 4.12 official, custom source installations with Flex).

Here’s a screenshot.

I tried re-installing steamVR, and nothing happened.
Sadly I can’t just proceed with a format since I have many projects and source installations on this pc and a full cleanup would lose me three days of work or more.

Please help!