Why is RunFullMemoryDiagnostic task running?!

[few34fwfs]

So I had noticed CPU usage from the system process when my PC was idle but I wasn't able to pinpoint the cause because as soon as I moved the mouse it stopped.
But this time it didn't. System was consuming 20% of my CPU and by checking which tasks were running I found it, disabled it, and problem fixed.
But
Why was it running in the first place? I got no blue screens.
And 2nd: If system can run memory diagnostic while Windows are running why can't I too?

 

[chrcoluk]

There is a task that will check your RAM for errors in the scheduled tasks, its one of many tasks that will only run when the system is idle, I tend to disable it on my rigs in my post install script, as I dont see the point of a automated resource churn RAM test, once you have a stable configuration its stable. On low end machines the thing can run for more than half a day.

schtasks /Change /TN "Microsoft\Windows\MemoryDiagnostic\RunFullMemoryDiagnostic" /Disable

Also if you want to run online memory tests you can do so, is many bits of software that can do it.