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Article Published by Marc Liron - Microsoft
MVP
http://www.instantvista.com/windows-vista-readyboost.html
What is Windows Vista Ready Boost?
Modern day software is more and more resource hungry, in every
aspect of computing power.
Demands increase continuously, regardless of whether it's CPU
frequency, hard-drive capacity or RAM memory that we are talking
about.
Although a RAM memory upgrade is often desirable, there are cases
when it cannot be immediately done. RAM memory is still quite
expensive so this may deter some and if you are upgrading an older
computer you may have already achieved the maximum amount that can
be physically installed.
So wouldn't it be nice to have a way to boost our computers
performance in such scenarios?
Welcome to Windows Vista Ready Boost!
Whilst physical memory such as RAM is quite expensive there is
another form of memory that is far cheaper and that is called Flash
memory.
How Does Windows Vista Ready Boost Work?
Your computer can access Flash memory around 10 times faster than
your hard drive so making it an ideal medium for Ready Boost
technology. Windows Vista can simply use the Flash memory as if it
was extra RAM.
Using a Flash memory device such as a USB memory key/stick (called a
flash drive by the operating system), Windows Vista can create an
intermediate caching layer on the device that logically sits between
RAM memory and your hard drive.
This can offer some great system performance gains.
Whenever a Flash drive is detected, Windows Vista will check to see
if it is fast enough to be used by Ready Boost as not all Flash
memory available is fast enough. If it passes the test, the user can
then allocate some memory for Ready Boost usage.
However Windows Vista will work out the amount of space is
recommended for optimal performance, but the user can choose to
ignore this recommendation, using more memory than recommended,
less, or none at all. Up to 4 GB of suitable flash memory can be
used.
Ready Boost is analogous to using the pagefile in some ways, but it
concentrates on storing different kinds of data. The performance
gain depends sensibly on what kind of data you are using. When
working with many small files, or when frequently having to access
small pieces of data, the performance is sensibly improved. For
larger files, the performance gain is often less in my experience.
I have personally seen BIG performance gains on older computers
upgraded to Windows Vista, that only had 512 Mb of RAM installed. By
adding a 2 Gb flash drive to one of the USB ports and then letting
Windows Vista choose the optimal amount of memory to use, the system
was notably more responsive when using multiple applications
(Internet Explorer, Outlook, Word, Excel and Windows Media Player)
at the same time.
The data stored on the flash drive is encrypted using the AES-128
encryption scheme. This ensures that the data is very difficult to
decrypt, should the flash drive be stolen.
The entire process is essentially hidden away from the user. Windows
automatically manages the newly available memory, and the flash
drive can be removed at any moment, without affecting the system.
Although most devices are already supported, some aren't. Namely,
external card readers are not supported for technical reasons, and
MP3 players are not supported because Windows does not recognize
them as actual disk volumes, but rather for what they are; MP3
player. However, the Ready Boost team is adding support for new
devices.
Ready Boost is also a very young technology. Although mature enough
to ship with Windows Vista, we can expect to see it with several
improvements in future versions of Windows or future Windows Vista
service packs.
For the technical folk reading this article Ready Boost consists of
two parts. A service in %SystemRoot%\System32\Emdmgmt.dll that runs
inside a Service Host process (%SystemRoot%\System32\Svchost.exe).
And a volume filter driver (%SystemRoot%\System32\Drivers\Ecache.sys.
When you insert a USB flash device into Windows Vista, the Ready
Boost service looks at the device to determine its performance
characteristics and stores the results of its test in the following
registry entry:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Currentversion\Emdmgmt
By the way if you are wondering why the notation Emd is used instead
of something like Ready Boost. During development of this technology
the working name was simply called External Memory Device, and so
Emd is simply short for that!
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