Removing Prefetch

[MagicHunter]

Hello,

 

Since Advanced SystemCare is to optimize PC, i also recommend adding a option to clean Prefetch =)

 

Prefetch is when a user boot up a program for the first time, a file is instantly created and placed in the Prefetch folder. The reason being that it will help the program boot up faster when you open it the second time.

 

However, as it piles up, It can do the opposite affect and slow the computer down.

 

 

Location:

My Computer > C Drive: > Windows > prefetch

 

 

If i am wrong about this. please feel free to correct me.

[detailer]

You're correct in terms of it's function.However,cleaning the prefetch folder is one of the most controversial subjects related to Windows.For instance,just Google "clean out prefetch",and look at every link contradicting the one before it.I look through mine after I've uninstalled some software to delete a related file if it's there.You can delete all the folder contents and they will rebuild themselves anyway.I think the rule of thumb is three reboots,but I believe this varies depending on the program and when it's accessed.You can also edit the registry to disable prefetch,or enable it for boot operations, or program operations,or both,which is the default.I believe a utility called CCleaner scours the prefetch for obsolete entries,but I don't use it myself.I'm more of a "do it yourselfer" in that area.

[solbjerg]

Hi detailer

Clayton was a very knowledgeable user that helped out in the forum a couple of years back, he wrote that there was no reason to clean the prefetch files EVER while they were automatically cleaned.

As far as I remember it was in the thread Install-Uninstall - in page 2

Cheers

solbjerg

 

 

 

You're correct in terms of it's function.However,cleaning the prefetch folder is one of the most controversial subjects related to Windows.For instance,just Google "clean out prefetch",and look at every link contradicting the one before it.I look through mine after I've uninstalled some software to delete a related file if it's there.You can delete all the folder contents and they will rebuild themselves anyway.I think the rule of thumb is three reboots,but I believe this varies depending on the program and when it's accessed.You can also edit the registry to disable prefetch,or enable it for boot operations, or program operations,or both,which is the default.I believe a utility called CCleaner scours the prefetch for obsolete entries,but I don't use it myself.I'm more of a "do it yourselfer" in that area.

[detailer]

Yes,I read that post along with hundreds of posts on many forums discussing the prefetch and what you should do or not do with it.Conclusion=The most controversial topic I've ever investigated regarding Windows.It's said that it "cleans itself", yet I've seen absolutely no evidence of this.I've deleted prefetch folders from my daughter's PC that were obsolete in terms of weeks(the software had been uninstalled)The closest I can come to the "self cleaning" claim is that prefetch will not store in excess of 128 files,and will delete any number needed to maintain that cap on the folder size.Also with respect to the Layout.ini file,we have the "three day maintenance cycle" where these files are presumably defragged.Before I got smart and opened up my wallet to purchase another Gig of Ram for that old HP,I read and played around with the prefetch for three days trying to substantiate the claims from both sides(clean/don't clean)I found it does rebuild itself most definitely,however I noticed it creates files that are IMHO not needed for the speedy operation of the system.If anybody can show me concrete evidence of a "cleaning schedule" of prefetch by Windows,that includes deleting obsolete files when the total number of files remains below 128,I'd very much like to see it.Currently on my daughter's PC are 98 files in prefetch-four of these are obsolete(software has been uninstalled).I'm waiting to see,if ever these are cleaned out by Windows.I suspect I will have to install enough new software and whatever else it takes to push the number up to the "magic 128" before these entries are deleted.There's room here for much debate,as forums I've checked out average 50-60 posts per thread on this subject,and I see no clear winner in this debate.I will maintain my own prefetch as that works best for me.The rest of the world can argue the point till Windows 14 arrives.

[solbjerg]

Very good detailer!!

Glad to see an investigation, I'll take a look myself then :-)

Cheers

solbjerg

 

 

Yes,I read that post along with hundreds of posts on many forums discussing the prefetch and what you should do or not do with it.Conclusion=The most controversial topic I've ever investigated regarding Windows.It's said that it "cleans itself", yet I've seen absolutely no evidence of this.I've deleted prefetch folders from my daughter's PC that were obsolete in terms of weeks(the software had been uninstalled)The closest I can come to the "self cleaning" claim is that prefetch will not store in excess of 128 files,and will delete any number needed to maintain that cap on the folder size.Also with respect to the Layout.ini file,we have the "three day maintenance cycle" where these files are presumably defragged.Before I got smart and opened up my wallet to purchase another Gig of Ram for that old HP,I read and played around with the prefetch for three days trying to substantiate the claims from both sides(clean/don't clean)I found it does rebuild itself most definitely,however I noticed it creates files that are IMHO not needed for the speedy operation of the system.If anybody can show me concrete evidence of a "cleaning schedule" of prefetch by Windows,that includes deleting obsolete files when the total number of files remains below 128,I'd very much like to see it.Currently on my daughter's PC are 98 files in prefetch-four of these are obsolete(software has been uninstalled).I'm waiting to see,if ever these are cleaned out by Windows.I suspect I will have to install enough new software and whatever else it takes to push the number up to the "magic 128" before these entries are deleted.There's room here for much debate,as forums I've checked out average 50-60 posts per thread on this subject,and I see no clear winner in this debate.I will maintain my own prefetch as that works best for me.The rest of the world can argue the point till Windows 14 arrives.

[JustDave]

I just took a look at the Prefetch folder on my office PC...

 

49 files

4.20 MB

No files older than mid-day yesterday. I use CCleaner but I have the prefetch folder unselected.

 

Personally I think the prefetch entries are like women: we're not meant to understand. Just nod and go along.

[detailer]

Thanks for the input Dave.I'm going to check out my rig later and see what's up there.

[solbjerg]

Hi Dave

I just looked too, and in my folder there are only files from today + a layout.ini file of 290 Kb.

But if I look for .pf files I find a few almost one year old and a few ½ a year old, most of the rest from this month.

Cheers

solbjerg

 

 

I just took a look at the Prefetch folder on my office PC...

 

49 files

4.20 MB

No files older than mid-day yesterday. I use CCleaner but I have the prefetch folder unselected.

 

Personally I think the prefetch entries are like women: we're not meant to understand. Just nod and go along.

[detailer]

Yes,further investigation shows files related to artwork projects of my daughter's that she has worked on in the past.They have either been completed,or at any rate not accessed to work on in weeks.Entries such as these should be seen as "old" and discarded.I would propose that some code or program writer develop a utility that would give the user control over what entries Windows is allowed to write to prefetch.Say a little monitor for the file with an allow/deny and "don't ask again option" would be great.Then some sort of a scan that identifies files over x# of days old with the option to delete those files.I agree that prefetch is useful,but I believe it's over-kill in respect to the number of files it writes.Remember,every time you boot,this is more data that Windows has to sort through to get you up and running.There has to be a better way to manage this program.

[JustDave]

I guess the real question is does Windows really look through all the prefetch entries on boot? Many of the .pf files on my PC have to do with Adobe and Autocad files; there's no benefit from scanning those files at boot. I also see an NTOSBOOT-B00DFAAD.pf file of 1.6 MB. From the name alone I'd expect that file to contain boot info.

[JustDave]

Found the following in the Prefetch section here.

 

An exception to the file name rule is the file that stores the boot's trace, which is always named NTOSBOOT-B00DFAAD.PF (a convolution of the hexadecimal-compatible word BAADF00D, which programmers often use to represent uninitialized data). Only after the Cache Manager has finished the boot trace (the time of which was defined earlier) does it collect page fault information for specific applications.

 

and...

 

When the system boots or an application starts, the Cache Manager is called to give it an opportunity to perform prefetching.

 

I can see why deleting NTOSBOOT-B00DFAAD.PF might slow down boot but I can't see why deleting the other .pf files would improve performance.

[solbjerg]

Great Dave!!

I'll find a place for your link - very informative!

Thank you!!

Cheers

solbjerg

p.s. Placed in Valuable Informative Links in Usage of IObit Products

 

 

Found the following in the Prefetch section here.

 

An exception to the file name rule is the file that stores the boot's trace, which is always named NTOSBOOT-B00DFAAD.PF (a convolution of the hexadecimal-compatible word BAADF00D, which programmers often use to represent uninitialized data). Only after the Cache Manager has finished the boot trace (the time of which was defined earlier) does it collect page fault information for specific applications.

 

and...

 

When the system boots or an application starts, the Cache Manager is called to give it an opportunity to perform prefetching.

 

I can see why deleting NTOSBOOT-B00DFAAD.PF might slow down boot but I can't see why deleting the other .pf files would improve performance.

[garybear]

Prefetch

 

I usually have prefetch unticked in CCleaner, and pay no attention to prefetch files. I took a look how ever just to see what I had. There were some really old files in there so I ticked clean prefetch in CCleaner. CCleaner removed all the old files and I took screen prints after it cleaned but I didn't do shots before, which I wish I had of done that also.I think I may leave prefetch ticked in CCleaner .Anyway here are my prefetch files in windows.I guess these are what you guys are talking about. Live well my friends [garybear]