What is the default cluster size setting when formatting a Windows NTFS partition on a hard disk drive larger than 2 GB?

Answer 1

The following table shows the default values that Windows XP uses for NTFS formatting. Drive size

(logical volume) Cluster size Sectors

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512 MB or less 512 bytes 1

513 MB - 1,024 MB (1 GB) 1,024 bytes (1 KB) 2

1,025 MB - 2,048 MB (2 GB) 2,048 bytes (2 KB) 4

2,049 MB and larger 4,096 bytes (4 KB) 8

The maximum default cluster size under Windows XP is 4 kilobytes (KB) because NTFS file compression is not possible on drives with a larger allocation size. The Format utility never uses clusters that are larger than 4 KB unless you specifically override that default either by using the /A: option for command-line formatting or by specifying a larger cluster size in the Format dialog box in Disk Management.

If you use the Convert utility to convert a volume from FAT to NTFS, Windows always uses a 512-byte cluster size. FAT structures are aligned on 512-byte boundaries; a larger cluster size does not allow conversion. Note also that in Microsoft Windows NT 4.0 and earlier, when a partition is formatted under Windows Setup, the partition is first formatted as FAT and then converted to NTFS. Therefore the cluster size is always 512 bytes when a partition is formatted in Setup. (This information does not apply to Microsoft Windows 2000 Setup or Windows XP Setup, which both format the partition according to your choice of a file system.)