Comments on: EnablePrefetcher in PrefetchParameters http://www.ghacks.net/2008/01/13/enableprefetcher-in-prefetchparameters/ A technology blog covering software, mobile phones, gadgets, security, the Internet and other relevant areas. Tue, 24 Nov 2009 04:07:45 -0600 http://wordpress.org/?v=2.8.6 hourly 1 By: Larry Miller http://www.ghacks.net/2008/01/13/enableprefetcher-in-prefetchparameters/#comment-556780 Larry Miller Wed, 03 Dec 2008 18:45:54 +0000 http://www.ghacks.net/2008/01/13/enableprefetcher-in-prefetchparameters/#comment-556780 Good article. One observation - values above 3 will be equivelant to valid values. The registry entry is used to independently control both boot and application prefetching. The result is obtained by ANDING bits 0 and 1, for a maximum value of 3. Setting a value over 3 will set bits 2 or 3 which are undefined. Microsoft has always warned that this paractice is dangerous. The equivelant values are as follows: 4 = 0 5 = 1 6 = 2 7 = 3 8 = 0 9 = 1 It should also be added that "cleaning" or deleting the contents of the prefetch folder will impair performance. It is based on a complete msunderstanding of how prefetch works. Proper prefetch operation requires that the Task Scheduler service be enabled and set to Automatic. Otherwise prefetch will be crippled, leading to impaired performance. Larry Miller Microsoft MCSA Good article.
One observation – values above 3 will be equivelant to valid values. The registry entry is used to independently control both boot and application prefetching. The result is obtained by ANDING bits 0 and 1, for a maximum value of 3. Setting a value over 3 will set bits 2 or 3 which are undefined. Microsoft has always warned that this paractice is dangerous.

The equivelant values are as follows:
4 = 0
5 = 1
6 = 2
7 = 3
8 = 0
9 = 1

It should also be added that “cleaning” or deleting the contents of the prefetch folder will impair performance. It is based on a complete msunderstanding of how prefetch works.

Proper prefetch operation requires that the Task Scheduler service be enabled and set to Automatic. Otherwise prefetch will be crippled, leading to impaired performance.

Larry Miller
Microsoft MCSA

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