dd if=/dev/sda of=/dev/null creates ever increasing load every second.
After minutes the load has moved up to 4.79
I've tried with two different discs in my system.
I wonder if it's a delay or problem with the SATA bus because one drive I have connected has recently failed.
I notice when drives fail that you get some IO/blocking issue when they don't respond properly.
Yes I believe it was, because here's the same disc after removing the dead........