Hi broli thanks for the pointer. We are using ESX 3.5 with the linux VM running RedHat 4 kernel (due to the app requirements).
We have just upped the VM to have 4 vCPUs to match the physical...
We have a VM running RedHat that seems to have very high system (kernel) utilisation compared to our physical servers running the same OS and workload that show normal system time utilisation.