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[1]) 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.[2]

Overview

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.[3]

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 a ReadyBoost tab is added to the drive's properties dialog where the amount of space to be used can be configured.[4] 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.[5]

ReadyBoost compresses and encrypts, with AES-128, all data that is placed on the flash device; Microsoft has stated that a 2:1 compression ratio is typical, so a 4 GB cache would usually contain 8 GB of data.[6]

Requirements

For a device to be compatible and useful, it must conform to these requirements:

Other considerations:

ReadyBoost is not available on Windows Server 2008.[12]

According to James Allchin, for future releases of Windows, ReadyBoost will be able to use spare RAM on other networked Windows PCs.[13]

Performance

A system with 512 MB of RAM (the minimum requirement for Windows Vista) can see significant gains from ReadyBoost.[14][15] In one test case, adding 1 GB of ReadyBoost memory sped up an operation from 11.7 seconds to 2 seconds. However, increasing the physical memory (RAM) from 512 MB to 1 GB (without ReadyBoost) reduced it to 0.8 seconds.[16] System performance with ReadyBoost can be monitored by Windows Performance Monitor.[17] As the price of RAM decreased and more RAM was installed in computers, the mitigations provided by ReadyBoost to systems with insufficient memory decreased.

The core idea of ReadyBoost is that a flash memory (e.g. a USB flash drive or a SSD) have a much faster seek time than a typical magnetic hard disk (less than 1 ms), allowing it to satisfy requests faster than reading files from the hard disk. It also leverages the inherent advantage of two parallel sources from which to read data, whereas Windows 7 enables the use of up to eight flash drives at once, allowing up to nine parallel sources. USB 2.0 flash drives are slower for sequential reads and writes than modern desktop hard drives. Desktop hard drives can sustain anywhere from 2 to 10 times the transfer speed of USB 2.0 flash drives but are equal to or slower than USB 3.0 and Firewire (IEEE 1394) for sequential data. USB 2.0 and faster flash drives have faster random access times: typically around 1 ms, compared to 12 ms for mainstream desktop hard drives.[18]

On laptop computers, the performance shifts more in favor of flash memory when laptop memory is more expensive than desktop memory; many laptops also have relatively slow 4200 rpm and 5400 rpm hard drives.

In versions of Vista prior to SP1, ReadyBoost failed to recognize its cache data upon resume from sleep, and restarted the caching process, making ReadyBoost ineffective on machines undergoing frequent sleep/wake cycles. This problem was fixed in Vista SP1.[19]

Limitations

Since flash drives wear out after a finite (though very large) number of writes, ReadyBoost will eventually wear out the drive it uses. According to the Microsoft Windows Client Performance group, the drive should be able to operate for at least ten years.[3]

See also

References

  1. Moulster, Ian (April 6, 2006). "SuperFetch, ReadyBoost and ReadyDrive: some new feature names for you". MSDN Blogs. Microsoft. Retrieved July 11, 2015.
  2. Russinovich, Mark (2007). "Windows Vista Kernel Changes". Microsoft. Archived from the original (PPTX) on September 12, 2007. Retrieved July 12, 2015.
  3. 1 2 3 Archer, Tom; Ayers, Matt (2006-06-02). "ReadyBoost Q&A". Tom Archer's Blog. MSDN Blogs. Retrieved 2008-01-11.
  4. Tom Archer (April 14, 2006). "ReadyBoost - Using Your USB Key to Speed Up Windows Vista". Tom Archer's Blog. Microsoft. Retrieved 2006-05-21.
  5. Marius Oiaga (October 12, 2009). "Windows 7 RTM ReadyBoost 256 GB of Memory Cache Support". SOFTPEDIA. SoftNews NET SRL. Retrieved 2013-01-09.
  6. 1 2 Mark Russinovich (March 2007). "Inside the Windows Vista Kernel: Part 2". TechNet Magazine. Microsoft. Retrieved 2007-03-01.
  7. 1 2 "Understand ReadyBoost and whether it will Speed Up your System". TechNet Magazine (Microsoft). Retrieved 2012-12-14.
  8. Microsoft Windows. "Windows 7 features - ReadyBoost - Microsoft Windows". Retrieved 2009-09-22.
  9. Microsoft Windows. "Using memory in your storage device to speed up your computer". Retrieved 2012-01-04.
  10. Ed Bott, ZDNet. "Is your flash drive fast enough for Vista's ReadyBoost?". Retrieved 2012-01-04.
  11. "ReadyBoost - Robbie's Benchmark". 14 April 2012. Retrieved 17 October 2014.
  12. Russinovich, Mark (March 2008). "Inside Windows Server 2008 Kernel Changes". Microsoft. Retrieved 2009-05-10.
  13. "Jim Allchin". 23 May 2006. Archived from the original on 2006-12-10. Retrieved 2006-11-01.
  14. AnandTech: Windows Vista Performance Guide
  15. Schmid, Patrick. "Windows Vista's SuperFetch and ReadyBoost Analyzed: Conclusion." Toms Hardware. 2007-01-31.
  16. AnandTech: Windows Vista Performance Guide
  17. Schultz, Greg. "Keep tabs on ReadyBoost with Windows 7's Performance Monitor." TechRepublic. 2010-03-24.
  18. "WD Scorpio Blue Mobile: Drive Specifications". Western Digital. June 2010. Retrieved 15 January 2011.
  19. Vista SP1 will fix critical ReadyBoost performance bug

External links

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