A load average of 4-5 is not too bad if you have 8 cores (you don't say how many you had)

Apache using 100% CPU is not unreasonable as long as it doesn't go on for too long as this may indicate some process hogging the resources. 

It can be hard to tell what those processes are actually doing. If it's there long enough to spot the process ID you could just use something like xdebug to work out what PHP is up to at the time.