Apenas para registro ... está a resposta :
$cpuutil=(get-counter -Counter "\Processor(_Total)\% Processor Time" -SampleInterval 1 -MaxSamples 5 |
select -ExpandProperty countersamples | select -ExpandProperty cookedvalue | Measure-Object -Average).average
If ($cpuutil -ge 90)
{Restart-Service MyService1, "My Service2", MyService3}
Else
{Exit}
O Powershell realmente torna a vida mais simples!