Understanding Superfetch in Windows 7

By KeeperOfThePizza
in The Fast Ring (Insider Previews)

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Grand Master

Subject Delta

Posted
Posted
The Resource Manager under Vista did not use bytes/second units - it used bytes per minute. When I saw "source 2007 materials.gcf" being read there and the "B/min" value was rising and rising and rising, I think it's fair to conclude it's actualy being read from the disk, and it was done so by svchost.exe with background IO - what other purpose of that than "superfetching" it? Oh, and the amount of free memory kept decreasing, so it wasn't just accessing the data, it was reading it into RAM.

Gotta be honest I don't have the answer to that one all I know is that isn't how its meant to behave, so something must have gone seriously wrong there

Proficient

RvXtm

Posted
Posted

Right now i only have 1,5 Gb's of DDR , and i find the Windows 7 superfatch more "adaptive" for smaller ram quantities. I feel photoshop loads just a little slower then vista sp1 . But that's just me and my prehistoric PC .

Grand Master

Udedenkz

Posted
Posted

Superfetch is a placebo which just speeds up the opening of applications, but doesn't really do anything after. I mean, if you have a slow hard drive then it will help, but for people with powerful systems or SSDs - this feature is nothing useful.

To whomever wanted all your RAM stuffed with superfetch, you obviously do not realize that some programs will assume that you have no RAM remaining and as such will run worse or not run due to a lack of RAM. Also this means that your OS will read GBs of data from your hard drive at boot which would reduce performance of your storage medium at that time.

I noticed -no- speed increase of -any- sort with superprefetch compared to having it off. There are better things to waste RAM on, like a RAMDISK for your temporary files.

/my $ 0.02

Grand Master

ToneKnee

Posted
Posted
Superfetch is a placebo which just speeds up the opening of applications, but doesn't really do anything after. I mean, if you have a slow hard drive then it will help, but for people with powerful systems or SSDs - this feature is nothing useful.

To whomever wanted all your RAM stuffed with superfetch, you obviously do not realize that some programs will assume that you have no RAM remaining and as such will run worse or not run due to a lack of RAM. Also this means that your OS will read GBs of data from your hard drive at boot which would reduce performance of your storage medium at that time.

I noticed -no- speed increase of -any- sort with superprefetch compared to having it off. There are better things to waste RAM on, like a RAMDISK for your temporary files.

/my $ 0.02

Superfetch should be disabled with SSD's since it can cause additional stress on the drives.

Community Regular

DJ-Light

Posted
Posted
Superfetch is a placebo which just speeds up the opening of applications, but doesn't really do anything after. I mean, if you have a slow hard drive then it will help, but for people with powerful systems or SSDs - this feature is nothing useful.

To whomever wanted all your RAM stuffed with superfetch, you obviously do not realize that some programs will assume that you have no RAM remaining and as such will run worse or not run due to a lack of RAM. Also this means that your OS will read GBs of data from your hard drive at boot which would reduce performance of your storage medium at that time.

I noticed -no- speed increase of -any- sort with superprefetch compared to having it off. There are better things to waste RAM on, like a RAMDISK for your temporary files.

/my $ 0.02

that's not true...

Personal test, Windows 7 7100 x64

boot > Open Firefox after 5 minutes of idle system with superfetch on = 2.2 seconds

boot > Firefox / 5 minutes idle / superfetch off = 4.6 seconds

Boot > Open notepad after 3 minutes of idle system with superfetch on = 0.5 seconds

Boot > Notepad/ 3 minutes idle /superfetch off = 1.4 seconds

and it continues...

I don't know, but with superfetch I see smaller numbers ;)

Grand Master

Subject Delta

Posted
Posted
Superfetch is a placebo which just speeds up the opening of applications, but doesn't really do anything after. I mean, if you have a slow hard drive then it will help, but for people with powerful systems or SSDs - this feature is nothing useful.

To whomever wanted all your RAM stuffed with superfetch, you obviously do not realize that some programs will assume that you have no RAM remaining and as such will run worse or not run due to a lack of RAM. Also this means that your OS will read GBs of data from your hard drive at boot which would reduce performance of your storage medium at that time.

I noticed -no- speed increase of -any- sort with superprefetch compared to having it off. There are better things to waste RAM on, like a RAMDISK for your temporary files.

/my $ 0.02

I disagree. The application doesn't look and see how much memory is free, it has to make a request to the OS. The OS will then unload some of the superfetched content to make way for the item in memory. Superfetched memory actually shows up as empty memory.

I have 8GB of ram and a quad core CPU, and I can still tell the difference between superfetched and non superfetched applications

Grand Master

ViperAFK

Posted
Posted

Superfetch uses just as much of my 4 gb of ram as vista did...

@jjrambo, ssd's are a loooong way off of becoming standard. Mechanical hdd are not going anywhere too soon.

Superfetch is a placebo which just speeds up the opening of applications, but doesn't really do anything after. I mean, if you have a slow hard drive then it will help, but for people with powerful systems or SSDs - this feature is nothing useful.

To whomever wanted all your RAM stuffed with superfetch, you obviously do not realize that some programs will assume that you have no RAM remaining and as such will run worse or not run due to a lack of RAM. Also this means that your OS will read GBs of data from your hard drive at boot which would reduce performance of your storage medium at that time.

I noticed -no- speed increase of -any- sort with superprefetch compared to having it off. There are better things to waste RAM on, like a RAMDISK for your temporary files.

/my $ 0.02

Even on an ssd it could possibly improve performance because ram is still magnitudes faster but it wouldn't be noticeable and it should be disabled as said above because it can cause more stress on ssds because of their limited writes.

On any traditional hdd system it should definitely be on. The whole point of it is to make apps open faster and it does it well...

And you completely contradicted yourself, saying it works and opens apps faster but is also a placebo, that makes no sense.

Proficient

jamesVault

Posted
Posted (edited)
http://jaysonrowe.com/2009/01/05/thoughts-...fetch-in-vista/ - read the paragraphs above and below the second screenshot.

I would consider this normal behaviour, because the .vdi file needs to be saved by VirtualBox. This disk activity is caused by VirtualBox.

Edited by jamesVault
Experienced

soonerproud

Posted
Posted
sorry, I'm using the Win7 Rc for a month! And it's not a bad install. :rolleyes:

sorry, that doesn't make you right. Before you go off half cocked and comment how wrong we are, you need to read up on the changes to SuperFetch first to understand why they were made and why it was for the better.

And quit using sorry before expressing your opinion each and every time. And learn to capitalize the first letter of your post too while you are at it. You should never be "sorry" for having a opinion, even if it is wrong.

Lets go back to basics here. I thought the general consencus was that Windows7 was much faster than Vista. The experiences here hint that the experence is actually slower? Please correct me if I'm wrong!

It is much faster than Vista on old or low end hardware. It is slightly faster than Vista on good hardware. It is just a very vocal minority claiming other wise.

Superfetch should be disabled with SSD's since it can cause additional stress on the drives.

Windows 7 will do that for you with Trim supported drives.

Veteran

Wakers

Posted
Posted

I have 7 installed on 2 machines, and have had it installed since the RC was released.

My desktop is running x64 and has 4gb of RAM.

My laptop is x32 and has 2gb of RAM.

Win 7 never uses more than 38% of the RAM on the laptop, and never more than 28% on the desktop, even with superfetch enabled.

I don't understand why on some people's machines they say its using 1.5gb just with superfetch? Are they looking somewhere other than task manager for the details?

Grand Master

ToneKnee

Posted
Posted
I have 7 installed on 2 machines, and have had it installed since the RC was released.

My desktop is running x64 and has 4gb of RAM.

My laptop is x32 and has 2gb of RAM.

Win 7 never uses more than 38% of the RAM on the laptop, and never more than 28% on the desktop, even with superfetch enabled.

I don't understand why on some people's machines they say its using 1.5gb just with superfetch? Are they looking somewhere other than task manager for the details?

That's because when you are reading the Task manager, you are reading RAM which is currently being used by applications and services. Windows doesn't add the Superfetch data to that percentage since it's actually free memory, and when an application needs it, it can do it instantly. I think this is to reflect what the actual usage is with applications/services rather than Windows just adding everything on to confuse people.

If you go to the task manager and look at the performance tab, there is a usage box under the 'Memory' indicator graph.

Total = Total system memory

Cached = How much Windows has cached using Superfetch

Available = How much memory is actual available (Free memory + Superfetch data)

Free = What memory is free after Superfetch and applications/services (Total minus Superfetch minus Current Application/Service usage)

Hope this helps.

Grand Master

Nagisan

Posted
Posted
Superfetch should be disabled with SSD's since it can cause additional stress on the drives.

+1, along with prefetch (dunno if theres a difference but it is a separate registry value), defragmenting, indexing and even readyboot (the thing that re-orders boot items for faster booting).

It was enabled from build 7000 to build 7100, did not try other builds yet.

Disable it ASAP......I get faster load times with all the above disabled on my SSD than I do with it enabled on a standard HDD.....all having it enabled does is wear the SSD out faster for a tiny increase in program load times (a much smaller increase than going from a HDD w/ superfetch to a SSD without superfetch).

As an example, Photoshop CS4 and Word 2007 both take ~2 seconds to load on my SSD without superfetch, on my HDD with superfetch they both took ~8-10 seconds.

Mentor

CdCViRus

Posted
Posted
I disagree. The application doesn't look and see how much memory is free, it has to make a request to the OS. The OS will then unload some of the superfetched content to make way for the item in memory. Superfetched memory actually shows up as empty memory.

I have 8GB of ram and a quad core CPU, and I can still tell the difference between superfetched and non superfetched applications

A minor correction: the OS doesn't need to "unload" anything from RAM. it simply overwrites the contents of RAM with the stuff it wants to load instead, so there is absolutely no additional performance penalty.

Grand Master

Julius Caro

Posted
Posted
Superfetch is a placebo which just speeds up the opening of applications, but doesn't really do anything after. I mean, if you have a slow hard drive then it will help, but for people with powerful systems or SSDs - this feature is nothing useful.

To whomever wanted all your RAM stuffed with superfetch, you obviously do not realize that some programs will assume that you have no RAM remaining and as such will run worse or not run due to a lack of RAM. Also this means that your OS will read GBs of data from your hard drive at boot which would reduce performance of your storage medium at that time.

I noticed -no- speed increase of -any- sort with superprefetch compared to having it off. There are better things to waste RAM on, like a RAMDISK for your temporary files.

/my $ 0.02

What? Could you elaborate on that? I thought apps worked with virtual memory, meaning that they don't really CARE about physical memory? And let's say that the app really is aware of its location in the physical memory, to get this information wouldn't they have to get it from windows itself? (meaning that even if superfetch was on, windows would report this sector of the RAM as 'free' to the apps?). I thought that , at all times, it is the OS that manages the memory. And "the app thinking there is no ram left and as such will run worse", I didnt know that apps decided to run WORSE at the thought of not having more ram. It's not the app that decides whether or not to use the page file, it is the OS.

Also, it's been reported that windows 7 waits until after boot to start loading the superfetch thing.

Grand Master

ToneKnee

Posted
Posted
What? Could you elaborate on that? I thought apps worked with virtual memory, meaning that they don't really CARE about physical memory? And let's say that the app really is aware of its location in the physical memory, to get this information wouldn't they have to get it from windows itself? (meaning that even if superfetch was on, windows would report this sector of the RAM as 'free' to the apps?). I thought that , at all times, it is the OS that manages the memory. And "the app thinking there is no ram left and as such will run worse", I didnt know that apps decided to run WORSE at the thought of not having more ram. It's not the app that decides whether or not to use the page file, it is the OS.

Also, it's been reported that windows 7 waits until after boot to start loading the superfetch thing.

The guy you quoted is completely mis-understands how Superfetch works.

Grand Master

Kirkburn

Posted
Posted
The guy you quoted is completely mis-understands how Superfetch works.

Yeah, I find it hilarious when random internet tech enthusiasts think they know better than the Windows developers about how Windows works.

Have they so little confidence in Windows that they think the devs would spend time developing stuff that is specifically detrimental to a PC's performance? How would that ever make sense from any perspective?

It's all very tin foil hat...

Grand Master

ToneKnee

Posted
Posted
Yeah, I find it hilarious when random internet tech enthusiasts think they know better than the Windows developers about how Windows works.

Have they so little confidence in Windows that they think the devs would spend time developing stuff that is specifically detrimental to a PC's performance? How would that ever make sense from any perspective?

It's all very tin foil hat...

People complain that Superfetch makes their systems slow, that can be true about Vista when it would Superfetch everything into the memory right after start up, but that's not what happens in Windows 7 since the system waits for you to be idle or not using much of the system, i.e. browsing the interwebs.

Another thing Windows 7 does (which I don't think Vista ever did) is do a WEI on your computer if you leave it on. For example, I was downloading some stuff on Usenet the other night and I just finished installing Windows 7, and I noticed that I needed to do a WEI to get my new scores, but I couldn't be bothered waiting 5 minutes for it to finish. Woke up the next day and noticed it did one over night. Pretty cool! :)

Proficient

jjrambo

Posted
Posted
+1, along with prefetch (dunno if theres a difference but it is a separate registry value), defragmenting, indexing and even readyboot (the thing that re-orders boot items for faster booting).

Disable it ASAP......I get faster load times with all the above disabled on my SSD than I do with it enabled on a standard HDD.....all having it enabled does is wear the SSD out faster for a tiny increase in program load times (a much smaller increase than going from a HDD w/ superfetch to a SSD without superfetch).

As an example, Photoshop CS4 and Word 2007 both take ~2 seconds to load on my SSD without superfetch, on my HDD with superfetch they both took ~8-10 seconds.

Word 2007 takes ~2 seconds to load on my Raid 0 setup without superfetch. As I said long time ago, if you even have good Raid 0 (with standard HDDs) setup Superfetch is useless.

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