Source: VMwareWolf

There have been early reports of a behavior new to ESX 3.5 and VirtualCenter 2.5 wherein after a VMotion (whether DRS initiated or not) CPU usage spikes and remains abnormally high. High CPU is seen on both OS perfmon and esxtop. A workaround has been found until this gets fixed.

Read the workaround at VMwareWolf

Edit (24-jan-08): Official work around from VMware’s KB

by Gabrie van Zanten