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Prefetch and BootVis

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This is one of those "For What It's Worth" posts. I'm not telling anyone to do this. I'm not saying that this is the end-all to better computing. I just thought it was very interesting, and wanted to share it here at GeeksToGo. Consider it my way of saying hello and making friends.

I did this for another forum. There was sort of a discussion going on about Prefetch and BootVis.

Ibis, this is partly for you, and partly out of my own curiosity.

I do not use nLite, as you may know. I do however delete many files from my XP installation. My Windows directory is 185MB.

I also keep a full XP installation image stored on another partition for testing purposes and comparisons. And I keep this image up-to-date same as I do the other.

Each installation is identical to the other. Each has the same programs installed. Each has the same settings and tweaks applied. Each is kept up with the latest drivers and Windows Critical Updates. Everything installed is exactly the same as the other. Every change made is exactly the same...right down to the appearance of my Desktop.

There are only two exceptions to this:

1) Services settings

2) Files removed

I cannot run BootVis on my 185MB image. I have COM+ disabled and all it's associated files deleted.

I can run BootVis on my full installation, as COM+ is enabled and none of its files have been deleted. (Also, if it matters, Windows Defragmenter is enabled on this installation; where it is removed on the other.)

Here are the Services settings I have on the full-installation image:


And these are the only files I removed from the full-installation image:


To figure out everything I have deleted on the 185MB installation...well, you'd kind of have to read my entire guide.

However, I can show you which Services I have enabled, disabled, and deleted, here:


On each installation, my reboot time is a consistent 31 seconds (given an oddball, occasional, 32 second reboot on each). I have always kept a curious check on this. (I was excited recently to discover that if I set Acronis Scheduler2 Service to manual, and not allow Acronis True Image Monitor to startup with my system, that it shaved 2 seconds off my reboot time.)

One more thing, I use PerfectDisk Defragmenter on both installations to manage my boot files, and I have always had Prefetch enabled (set to "3" in the registry) on both installations.


The Prefetch registry location, and settings defined:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters

Dword value = EnablePrefetcher

0 = Disable,
1 = App launch prefetch
2 = Boot Prefetch
3 = Both (recommended)


Now that we have those reference points established, let me show you my results.

With my full installation, (reboot time being a consistent 31 seconds), when I run BootVis, my consistent reboot time remains at 31 seconds. If I then, set my Prefetch to "0" in the registry (disabled), my reboot time gains 2 seconds, making it now 33 seconds. Now, if I then keep that "0" setting, and purge the Prefetch folder of all it's files, and defragment using PerfectDisk, my reboot time goes down a second, to 32 seconds. So I gained 1 second on my reboot time on my full installation by doing this.

As I said, I cannot run BootVis on my 185MB installation. However, when I disable the Prefetch in the 185MB installation, my 31 second reboot time gains 1 second, making it 32 seconds. Then, leaving Prefetch disabled, and now purging the Prefetch folder of all its files, defragmenting using PerfectDisk, my reboot time reverts once again to its 31 seconds.

You know something? I really learned something with all this.

By having the Prefetch disabled, and the Prefetch folder purged of all its files, on my 185MB installation, there is absolutely no difference in my reboot times. On the other hand, should I do the same for my full installation image, it adds 1 second to my reboot time.

You know, I liked those results so much, I've included them in PART 5 of the guide.
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Personally I would never disable prefetching. I do empty the prefetch folder every now and then but I would never stop it. It is needed if you want the PageFile to work properly, which you do for overall system proformace. My boot time on 512mb ram and 3 ghz cpu is 24 seconds.

This is just what I think, I might be wrong.
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