The load average doesn't really tell us much, it would be the idle percentage that knowing it would help out the most. A high load average may just mean there's a lot of people using a lot of the sites on the server, not that it's having a breakdown. Now, if the idle percentage (percent of the CPU not being used) goes down, then it's in trouble. The problem is, there's no way to tell what it is from within PHP, barring executing the top command and parsing it, which would do more harm than good.