Samsung has launched a tool for resolving a nasty performance-killing bug in its 840 Evo and 840 Evo mSATA solid-state storage devices, which includes a firmware update to fix the flaw and a calibration tool for restoring performance to existing data.
When Samsung released its 840 Evo family of SSDs, it didn't realise that there was a flaw in its algorithm for detecting the voltage levels of its triple-level cell (TLC) NAND flash memory. The result: over a period of time, usually around a month, data stored on the drive began to degrade in a way that required the controller to make multiple read passes - crippling performance. It's a nasty bug, and one for which there has been no real solution until now.
The Samsung SSD 840 EVO Performance Restoration Software, to give the utility its full name, is promised by Samsung to fully resolve the issue - including restoring high-speed access to data already stored on affected drives without requiring a backup, wipe and restore cycle. The free tool first upgrades the firmware of the affected drives - to version EXT0CB6Q for the SATA models and EXT42B6Q for the mSATA models - which adds an improved voltage-calibration algorithm to prevent future degradation. The tool then scans the drive for data which has already begun to degrade and recalibrates its cells.
The tool supports MBR and GPT partition types on Intel and AMD chipsets, providing the drives are not part of a RAID array or connected via non-SATA means, but warns that those with AMD drivers installed will need to make sure they are on the latest version before attempting to repair their drives.
The software is available as a free download from Samsung's website
for Windows now, with a bootable DOS-based version for users of OS X, Linux and other non-Windows operating systems promised by the end of the month, with the caveat that the performance restoration feature is limited to NTFS partitions only.