https://wccftech.com/monster-hunter-world-pc-patch-released-fixes-cpu-utilization-issues/

Monster Hunter World suddenly got a couple of critical issues with the recent release of the Iceborne expansion on PC. One was the abnormally high CPU utilization, while another bug corrupted save data in some cases.

CAPCOM released a new patch (roughly 250mb in size) a few hours ago that should fix both of those issues in Monster Hunter World, as detailed below.