I had the same problem with a strong PC and did the following:
1. Open "regedit" (search in windows menu)
2. Press F3 and search for 51dea550-bb38-4bc4-991b-eacf37be5ec8
3. Change the value of the files "Valuemin" and "Valuemax" to 0
Since then it runs truly smooth as fuck. Method was posted on twitter, when FalleN had problems on LAN. Solution is from a FACEIT admin.