Superfetch... how exactly does it work

[BunBun]

Yeah, it would be nice to have more srews to turn. But then, do you want to put the extra code into the system for the 2% of users that know how to deal with that and understand the implications.

They have it in other places for less then 2% of the user base. And considering the potential benefit from such settings...

And if coded properly there would be no additional overhead when the power user settings are disabled.

 

[ikjadoon]

Actually, it's better to leave it ON for SSDs. I mean, if you read those articles.....it says it puts stuff into the RAM. Which is hella faster than any SSD I've seen.

Windows 7 knows this. It disabled defrags on my SSD, but left Superfetch on.

 

[whs]

Actually, it's better to leave it ON for SSDs. I mean, if you read those articles.....it says it puts stuff into the RAM. Which is hella faster than any SSD I've seen.

Windows 7 knows this. It disabled defrags on my SSD, but left Superfetch on.

Yeah, I have tried both ways and did not see any difference. If you leave it off, you have less writes to the SSD which is positive. The OCZ people (on their forum) recommend to turn it off and I asume they know why.

 

[ikjadoon]

Tony posted a guide about the tweaks he does to his SSD's over at OCZ, but he says MS says that Superfetch should be turned off for SSDs.

I like the fact that's on. Don't know why now, but just feel better, lol.

 

[whs]

Tony posted a guide about the tweaks he does to his SSD's over at OCZ, but he says MS says that Superfetch should be turned off for SSDs.

I like the fact that's on. Don't know why now, but just feel better, lol.

One more reason to ask the question why they do not turn it off at the Win7 installation. I noticed that too.

 

[ikjadoon]

Tony posted a guide about the tweaks he does to his SSD's over at OCZ, but he says MS says that Superfetch should be turned off for SSDs.

I like the fact that's on. Don't know why now, but just feel better, lol.

One more reason to ask the question why they do not turn it off at the Win7 installation. I noticed that too.

This is what MS says:

Will Superfetch be disabled on SSDs?

Yes, for most systems with SSDs.

If the system disk is an SSD, and the SSD performs adequately on random reads and doesn’t have glaring performance issues with random writes or flushes, then Superfetch, boot prefetching, application launch prefetching, ReadyBoost and ReadDrive will all be disabled.

Initially, we had configured all of these features to be off on all SSDs, but we encountered sizable performance regressions on some systems. In root causing those regressions, we found that some first generation SSDs had severe enough random write and flush problems that ultimately lead to disk reads being blocked for long periods of time. With Superfetch and other prefetching re-enabled, performance on key scenarios was markedly improved.

?? Are ours all just too slow, then?

 

[logicearth]

If you are wanting to know the deep down core workings of SuperFetch, then the Windows Internals 5th Edition is the book you want.

 

[whs]

Are ours all just too slow, then

Thanks for sharing the passage. Are ours too slow? I don't think so. Mine are last generation OCZ (Vertex) and Intel (25M). If those don't qualify, what does.

then the Windows Internals 5th Edition is the book you want.

Logicearth, could you provide a link please.

 

[logicearth]

Logicearth, could you provide a link please.

Windows Internals Book

 

[nate42nd]

I have learned if you turn if off, it affects other services. I have an SSD in both of my main systems. I didn't notice much change, other than I could not use other services. (can't remember which ones) but I ended up turning it back on recently so I could use other services. FYI

 

[whs]

Logicearth, could you provide a link please.

Windows Internals Book

Thanks.

 

[djmauro]

i skipped some posts, so not sure if its been talked about already but personally it seems to be more use for systems with more RAM. But that depends - what kind of user are you?
I use large variety of software and it can be different every day or hour.
After monitoring ram usage, in about hour it did increase from my ~400mb idle to 1.2GB and i do only have 2gb installed.
So Using more different software, specially those that use more memory (games, audio workstations) i found myself running out of RAM and using page file and lots of RAM was full of crap.

For a casual user whos everyday routine is more or less same its a good option. Or if u got lots of ram and having 2-3gb of it filled would make no difference.

Superfetch is just a temp. way to fix the outdated data transfer methods and devices.
SSD may be faster but everything inbetween - cabels, controllers etc are still inefficient.

 

[whs]

Superfetch is just a temp. way to fix the outdated data transfer methods and devices

Absolutely right. It is just a means to overcome the access delay on a rotational disk. For SSDs it does not seem to do anything (just wears the SSD). I have been running with and without (on the SSD) and have not noticed any difference - but that could also be my way of using the system.

 

[logicearth]

So Using more different software, specially those that use more memory (games, audio workstations) i found myself running out of RAM and using page file and lots of RAM was full of crap.

That is not SuperFetch that is taking your memory. The space allocated to SuperFetch is not counted among the usage. To see the usage in Task Manager you need to go to Performance and look at "Cached" under the Physical Memory group. Or a better view is the Physical Memory diagram in Resource Manager. However, your assumptions of SuperFetch, are wrong. The memory taken up by SuperFetch is fully usable and redeemable when required, it takes up zero memory for applications.

 

[BunBun]

i skipped some posts, so not sure if its been talked about already but personally it seems to be more use for systems with more RAM. But that depends - what kind of user are you?
I use large variety of software and it can be different every day or hour.
After monitoring ram usage, in about hour it did increase from my ~400mb idle to 1.2GB and i do only have 2gb installed.
So Using more different software, specially those that use more memory (games, audio workstations) i found myself running out of RAM and using page file and lots of RAM was full of crap.

For a casual user whos everyday routine is more or less same its a good option. Or if u got lots of ram and having 2-3gb of it filled would make no difference.

Superfetch is just a temp. way to fix the outdated data transfer methods and devices.
SSD may be faster but everything inbetween - cabels, controllers etc are still inefficient.

A couple points wrong in your post. First superfetch is bad for those with lots of ram as it just increases disk thrashing that much more trying to fill up all that ram with stuff (that probably wont get used for users like myself. The ram used by superfetch is also availible to what ever program wants it as it is cache, not used ram.

You are right about using lots of different software, superfetch impedes that as while you are running that software superfetch is still cacheing stuff from the HDD slowing down it's access and saturating the south bridge chip subsystem while you are trying to work.

And about your last comment. The only outdated devices are rotational disks. Controllers, cables, etc are all capable of a lot more bandwidth then what we are currently using. However this is done by design as the true potential of our current tech is used in raid not stand alone devices.

Bottom line superfetch helps speed up the loading of applications that you use regularily (it does nothing however for operating programs, just there load times so I dont see how they argument it speeds up your computer). Other wise it slows down the operation of others. Also until it figures out what your doing and optimizes for that it really doesn't do much and for me it never gets a chance as I do different stuff all the time and when im not useing the computer it is a sleep and I also disable the built in scheduled defragmenter... so I leave superfetch off.

 

[logicearth]

You are right about using lots of different software, superfetch impedes that as while you are running that software superfetch is still cacheing stuff from the HDD slowing down it's access and saturating the south bridge chip subsystem while you are trying to work.

No, it does not impede that in anyway. SuperFetch only works while the I/O for the system is free. It will not saturate or slow down your system while you are working.

Instead of making assumption, wrong assumptions please read Windows Internals 5th Edition.

 

[ikjadoon]

Superfetch is just a temp. way to fix the outdated data transfer methods and devices

Absolutely right. It is just a means to overcome the access delay on a rotational disk. For SSDs it does not seem to do anything (just wears the SSD). I have been running with and without (on the SSD) and have not noticed any difference - but that could also be my way of using the system.

But, see, Superfetch caches to the RAM. Anything that is cached in RAM will by definition be accessed and read faster than on an SSD.

IDK.

~Ibrahim~

 

[djmauro]

But cache still uses up the RAM storage capacity... so it should count as a usage, it still fills up RAM.

I guess the superfetch related massive ram usage is a bug of the specific version.

 

[logicearth]

But cache still uses up the RAM storage capacity... so it should count as a usage, it still fills up RAM.

I guess the superfetch related massive ram usage is a bug of the specific version.

RAM you are not using. RAM not in use is being wasted, hence SuperFetch uses it so not to waste it. But as soon as an application requires space in use by SuperFetch, the space is overwritten not paged out. Zero overhead.

 

[whs]

I guess the superfetch related massive ram usage is a bug of the specific version.

I don't think so. I think it is just a misinterpretation on your part. The more RAM it uses, the better it is (in general). There may be some very specific cases where that is not true, but I cannot think of any.