Before Mavericks I used Snow Leopard and VM ware fusion 3 for running Win XP. The combination worked really good. System early 2010 MBP 8GB i5 Now after the update I have to use Fusion 6 but the minute I start the VM the CPU runs hot between 90 and 100°C and the fans run at 6000 rpm all the time. From the activity monitor I get that the 'vmware-vmx' uses 105% of the cpu. I tried the suggestions for the problem on the vmware forums but could not fix it. I installed virtual box and it also seems to use as much CPU as possible. At least with virtual box there is a option to limit the CPU max but the performance of vmware is much better. Anybody with similar problems? How is the CPU usage of Parallels? Has it something to do with Mavericks?