Choosing NTFS Cluster Size in windows

[Lightbringer-]

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Edited December 11, 2023 by Lightbringer-

[wht36]

I'm not an expert, but I was also interested in this.

As far as I can tell, there is no established speed benchmark proving that cluster size >4kb matters. Although a cluster size of 512 bytes is said to hurt performance when you have a large disk.

Windows uses the following defaults

* 512 bytes: 0 MB to 512 MB

* 1KB: 513 MB to 1 GB

* 2KB: 1 GB to 2 GB

* 4KB: 2 GB+

NTFS compression only works for 4kb and below (and that is the reason for the 4kb default). Note that decompressing on the fly may be faster than reading from the hard disk if you have a fast CPU.

I've read somewhere that Microsoft only recommends a large cluster size for servers and claims that the difference is negligible in home use.

What is recommended by all is to switch off indexing service (and it is switched off by default in the newer editions of XP).

If you do not have legacy programs that use the 8.3 filename storage method, you can also tell windows not to create a separate 8.3 filename entry (fsutil behavior set disable8dot3 1). Legacy programs includes all 16bit / DOS programs as well as programs that use the old uninstallers (apparently there are quite a few). Switching off last access may also help (fsutil behavior set disablelastaccess 1), but interferes with backups and restores.

Finally Microsoft recommends that users do not disable prefetch. It is claimed that prefetch allows windows to load executables and their required dlls in optimal sequence, thus speeding up load time.

Edited June 15, 2009 by wht36