My mobile workstation (i7, 16GB RAM) became really slow (even the mouse moves are shown with 1FPS), CPU usage at 100% even when nothing at all was running. After a few minutes even worse.
I have rebooted and tried to run an offline BitDeffender scan, which could not manage to parse a 100MB file in 10s.
Then I booted up using a mobile HDD, over just a USB2 cable. And it is even so faster like a rocket and with normal CPU usage.
Now I am suspecting my mSATA SSD (Samsung EVO 840)
Then I have downloaded Samsung SSD Magician and HDDTune and ran some tests:



The benchmarks look really meaningful:



Really low minimum and really high CPU usage, but even the maximum transfer rate is far below specs.
The SMART health status is OK:
And here is the speed map:

Is this the end of the SSD or the end of something on the motherboard - quite not uninteresting from cost point of view?