ReadyBoost

ReadyBoost

A component of Microsoft Windows
ReadyBoost as it appears in Windows 10.
Details
Type	Disk Cache
Included with	Windows Vista and later
Service name	ReadyBoost (EMDMgmt)
Description	Provides support for improving system performance using ReadyBoost.
Related components
ReadyDrive, SuperFetch

ReadyBoost (codenamed EMD) is a disk caching software component developed by Microsoft for Windows Vista and included in later versions of the Windows operating system. ReadyBoost enables NAND memory mass storage devices, including CompactFlash, SD cards, and USB flash drives, to be used as a write cache between a hard drive and random access memory in an effort to increase computing performance. ReadyBoost relies on the SuperFetch technology and, like SuperFetch, adjusts its cache based on user activity. Other features, including ReadyDrive, are implemented in a manner similar to ReadyBoost.

Using ReadyBoost-capable flash memory (NAND memory devices) for caching allows Windows Vista and later to service random disk reads with better performance than without the cache. This caching applies to all disk content, not just the page file or system DLLs. Flash devices typically are slower than a mechanical hard disk for sequential I/O, so, to maximize performance, ReadyBoost includes logic that recognizes large, sequential read requests and has the hard disk service these requests.

When a compatible device is plugged in, the Windows AutoPlay dialog offers an additional option to use the flash drive to speed up the system; an additional ReadyBoost tab is added to the drive's properties dialog where the amount of space to be used can be configured. The minimum cache size is 250 MB. In Vista or with FAT32 formatting of the drive, the maximum is 4 GB. In Windows 7 with NTFS or exFAT formatting, the maximum cache size is 32 GB per device. Windows Vista allows only one device to be used, while Windows 7 allows multiple caches, one per device, up to a total of 256 GB.