My Samsung SSD 840 EVO was suffering from the apparently well known problem that 'old' files (files which have been written a long while ago and not touched since) had slow read transfer rates (as low as 5 MBytes/s in places, 29 MBytes/s for some big files I had).
I have a Zotac server without a CD drive, so I needed to run the Samsung Performance Restauration tool. I used the DOS / Mac variant which is a DOS bootable disk which contains the update tool. The easiest way to prepare the USB stick is NOT to use the USB zip provided by Samsung but to use the *.iso file (Samsung_Performance_Restoration.iso) instead:
- Mount the ISO file and get the file ISOLINUX/BTDSK.IMG from it.
- dd the BTDSK.IMG directly onto a USB stick
- boot from the USB stick and follow the instructions
On my Zotac machine when booting from this USB stick I got a couple of broken error messages about not being able to boot from device XYZ, but it booted OK from the stick after a couple of seconds.
The performance restauration procedure took 4.5h for a 1TB SSD (60% full) and about 15h for another 1TB SSD (95% full), so expect this to take some time.
Both SSDs were not erased by the procedure.