Windows, solid-state disks, and 'trim'
By Fred Langa
It's a little-known fact that all solid-state disks — all of them — suffer inevitable performance declines over time.
It's also little known that Windows 7 and Server 2008 are currently the world's only operating systems to fully implement the new trim command that helps forestall this speed decline.
The Achilles' heel of all solid-state drives
Reader Peter Jackson is frustrated by the diminishing performance of his solid-state disk drive (SSD):
"I have a 64GB solid-state hard drive, but no way to restore it to factory-new condition. It has to do with getting the 'pages' to read as empty and not just overwritten. It's important to all SSD users, as the performance degradation is something [all SSDs] eventually suffer from.
"The few solutions I've found are very complex; so far, I haven't been able to get any of them to work. My SSD seek times degrading from .1 [millisecond] to .4 or .5 may sound silly, but it's not."
Performance degradation over time is a known issue with all SSDs, Peter. There are a number of contributing factors — I'll come back to this in a moment — but some of the worst culprits are standard disk operating commands that were originally designed for use on magnetic, spinning-platter hard drives. SSDs operate differently, and that leads to problems — especially when attempting to reuse previously accessed data blocks, such as the former location of deleted files.
To correct this problem, most current SSDs support a new command called trim. This SSD-specific command does just what you want — it automatically clears out old, overwritten data.
The trim command specification is being made a computing standard by the International Committee for Information Technology Standards, so all OSes will eventually support trim. But for now, only Windows 7 and Server 2008 fully support the trim command. While Linux 2.6.28 is SSD-aware, its partial implementation of trim falls short of Windows' full support.
That's worth repeating: Right now, Win7 and Server 2008 are the only OSes that offer full, native support for trim. They're the only OSes that let you get the most out of an SSD right out of the box!
Absent a trim-aware OS, you either have to rely on the workaround routines built into some SSD firmware or use add-on trim-ming tools. For example, G. Skill's Wiper software is designed specifically for its Falcon Series SSDs; you can download and read about the utility on the
G. Skill site. "Hdparm," a Linux-based tool for modifying hard drive parameters, includes experimental trim scripts in version 9.17 and higher. More information is available in an
LWN.net article, and Hdparm itself is downloadable from a
SourceForge page.
However, one look at the extensive cautions and warnings on those pages, and you'll see why having trim baked into your OS is obviously the best way to go.
SSD performance is a complex topic. WindowsITPro's article
101947 by John Savill explains why all SSDs suffer gradual performance slowdowns. Article
101966 by the same author explains how a trim-aware OS can help.
A longer Computerworld
analysis of SSD performance by Lucas Mearian delves more deeply into why SSD slowdowns are inevitable. All three of these articles include links to more information on the subject.
But Peter — and anyone else using an SSD — the bottom line is this: Upgrade to Win7 or Server 2008, pronto!