https://bugzilla.kernel.org/show_bug.cgi?id=90741
--- Comment #7 from Gustaw Smolarczyk wielkiegie@gmail.com --- Unfortunately, it was a false lead. Disabling iGPU didn't help in any way on 3.18.1.
Additionally, I take back the "less pauses in 3.18.0 and later" thing. 3.18.1 was horrible just now (same as any kernel after the commit bisected).
Is there any way I can help investigating it more?