Does Windows 7 SuperFetch cause "un-necessary" wear on Hard Drive and RAM?

[GundamF91]

Was having a debate with my buddy about his new system. He disabled the SuperFetch in Win7. The reason is that as SupreFetch accesses HDD and dumps data on RAM, it is causing unnecessary work, and wear and tear for both components. I have never thought about that until that time. Now that he's got me thinking, I wonder how much wear would be on the HDD and RAM due to SuperFetch.

If the HDD is being accessed when OS didn't have to, then theoretically that is extra wear on it. I'd presume there is actually more wear to HDD since it is mechanical whereas RAM would not really care for having its rows and columns refreshed as much. The counter argument would be that eventually the data prefetched would be accessed sometime during the computing session, so it does not wear on the HDD at that later time. On the other hand, that time may never happen.

Maybe the question is how accurate is SuperFetch, and how often does it keep fetching stuff just for the sake of it. Are there stats for that?

I think in the grand scheme of things, wear would be minor, and the added benefit of reduced load time may be worth it. But there is something to be said about the actual wasted wear. what do you all think?


PS> while writing this question, I can't shake the mental image of a wife spending time to make a nice dinner ready, but when the husband comes home, only to find out that husband says "I'm not hungry" or "this is not what I want for dinner". And then have to redo it while throwing away the dinner.

 

[lxskllr]

Ram is irrelevant. The HD would theoretically have more wear, just like taking the floor mats out of your car theoretically gets you better gas mileage. It isn't enough to worry about.

 

[Nothinman]

I think in the grand scheme of things, wear would be minor, and the added benefit of reduced load time may be worth it.

This. The computer is there to work for you, let it do all it can to save you time.

 

[Bateluer]

Something else to keep in mind, by the time there's any 'real' issue, it'll be time for new hardware anyway. Shoot, Newegg's selling 1TB drives for 55 dollars right now.

 

[SimMike2]

My refrigerator gets a ton of extra wear and tear keeping all my food cold. Just think how long it would last if it didn't do this. It would last forever. Nuff said. This sucker gets unplugged right now!

 

[JohnOfSheffield]

Ram is irrelevant. The HD would theoretically have more wear, just like taking the floor mats out of your car theoretically gets you better gas mileage. It isn't enough to worry about.

Wouldn't it be less wear on the HDD though?

I mean, if the app (or files) is already in RAM, wouldn't that mean that it wouldn't have to be read from HDD as often? Or doesn't Windows superfetch and Linux prefetch work in the same way?

 

[lxskllr]

Wouldn't it be less wear on the HDD though?

I mean, if the app (or files) is already in RAM, wouldn't that mean that it wouldn't have to be read from HDD as often? Or doesn't Windows superfetch and Linux prefetch work in the same way?

Superfetch loads what it /thinks/ you'll need, not necessarily what you WILL need. That being the case, the HD will be doing some work for nothing, but it's not a big deal with regards to drive wear.

Edit:
I guess I didn't completely finish the thought. Actual drive use would be hard to quantify without fully analyzing the system over time, with, and without Superfetch enabled. That might be an amusing experiment for someone, but I couldn't be arsed to do it. Drive wear would be dependent on how accurate Windows was at anticipating need.

 

[GundamF91]

Has Microsoft said how they determine the algorithm for SuperFetch? How does it determine what to load, and when to update its trace list and removed the old stuff and put in new stuff? The answer may be how accurate is SuperFetch, or if it's just a marketing gimmick.

 

[lxskllr]

Has Microsoft said how they determine the algorithm for SuperFetch? How does it determine what to load, and when to update its trace list and removed the old stuff and put in new stuff? The answer may be how accurate is SuperFetch, or if it's just a marketing gimmick.

It loads stuff based on historic use, and it changes per time of day. For example office type stuff might be preloaded early in the day, while entertainment type stuff might be preloaded in the evening.

 

[JohnOfSheffield]

Superfetch loads what it /thinks/ you'll need, not necessarily what you WILL need. That being the case, the HD will be doing some work for nothing, but it's not a big deal with regards to drive wear.

Edit:
I guess I didn't completely finish the thought. Actual drive use would be hard to quantify without fully analyzing the system over time, with, and without Superfetch enabled. That might be an amusing experiment for someone, but I couldn't be arsed to do it. Drive wear would be dependent on how accurate Windows was at anticipating need.

Really? I thought it just loaded commonly used files (programs, libs, user files, whatever) into cache and kept it there until the memory as nearly needed when it would be smart and let the least utilized files go as well as using some kind of tracking to see which files the user actually uses and only keep those within a certain usage in superfetch?

Perhaps i just don't get what it is and it works nothing like prefetch?

Naturally, to make it work right, you'll need to use sleep modes instead of restarting or shutting down your computer, but in this day and age, who turns off their computer when you can hibernate it.

 

[lxskllr]

You pretty much got it. It's a "smart" prefetcher that tries to have what you need before you need it. Most people don't have enough ram to load everything they need, so Windows tries to make an educated guess as to what's really important. It won't hold cached data at the expense of memory you need now, but it tries to have what you need ready for you.

 

[gsaldivar]

Negligible difference. Turn it on and don't worry about it.

 

[JohnOfSheffield]

You pretty much got it. It's a "smart" prefetcher that tries to have what you need before you need it. Most people don't have enough ram to load everything they need, so Windows tries to make an educated guess as to what's really important. It won't hold cached data at the expense of memory you need now, but it tries to have what you need ready for you.

Well that's just like prefetch then, but i don't get how that would stress the HDD more considering that what it actually does is decrease the amount of HDD IO for regular usage, if it didn't, it'd be entirely useless.

Doesn't it mostly keep recently used files in cache if you keep your computer on at all times? I suppose if you restart your computer very often and use a variety of different applications then the superfetch would just be confused and load the wrong files but i doubt anyone uses their computer like that.

 

[lxskllr]

Well that's just like prefetch then, but i don't get how that would stress the HDD more considering that what it actually does is decrease the amount of HDD IO for regular usage, if it didn't, it'd be entirely useless.

Doesn't it mostly keep recently used files in cache if you keep your computer on at all times? I suppose if you restart your computer very often and use a variety of different applications then the superfetch would just be confused and load the wrong files but i doubt anyone uses their computer like that.

It keeps recently used files as well as files it thinks you'll need in ram. It could cause additional hd use if it guesses I'm going to play UT2k4, and loads the files, but I really play Bioshock instead. It'll have to then load the Bioshock files, so the UT2k4 load will have been a waste. If that happens a lot, it could cause more hd use, but the whole thing's just a slightly amusing distraction. It isn't going to cause your hd to die sooner, at least not in any significant way.

I don't think restarting the computer affects Superfetch. I believe it keeps a record from session to session.

 

[Modelworks]

I turn it off but not because of HDD stress. I turn it off because I rarely run the same applications in any sort of pattern so superfetch is useless for me. I also turn off windows search because it is just as useless to me. I use everything for searches.

 

[JohnOfSheffield]

It keeps recently used files as well as files it thinks you'll need in ram. It could cause additional hd use if it guesses I'm going to play UT2k4, and loads the files, but I really play Bioshock instead. It'll have to then load the Bioshock files, so the UT2k4 load will have been a waste. If that happens a lot, it could cause more hd use, but the whole thing's just a slightly amusing distraction. It isn't going to cause your hd to die sooner, at least not in any significant way.

I don't think restarting the computer affects Superfetch. I believe it keeps a record from session to session.

I thought it was smart enough to know which ones were used most, that might mean that some of each of those games files were already loaded while the rest would not be (i assume you know what i'm talking about) which would mean that not all files would be pre-read if there isn't enough memory to do that, of course. In combination with readyboost that should really reduce wear and tear on the HDD by ... not enough to make it noticeable.

If you rebeoot your computer it would have to reread those files into superfetch, wouldn't it? Superfetch is gone from ram when rebooted so that might cause extra wear.

I don't think it matters either way either, i'm just trying to figure out whether superfetch and preload works in the same way.

 

[JohnOfSheffield]

I turn it off but not because of HDD stress. I turn it off because I rarely run the same applications in any sort of pattern so superfetch is useless for me. I also turn off windows search because it is just as useless to me. I use everything for searches.

So it doesn't keep a pattern of what apps you use? Some of the same files are almost always used when using different apps so just that would make it worth keeping it on, and why wouldn't you? Is there an upside to NOT keeping it on?

Is there a need to NOT keeping windows search on?

If so, what are they? I honestly don't know so if you can educate me on this matter i would like to know.

 

[Modelworks]

So it doesn't keep a pattern of what apps you use? Some of the same files are almost always used when using different apps so just that would make it worth keeping it on, and why wouldn't you? Is there an upside to NOT keeping it on?

Is there a need to NOT keeping windows search on?

If so, what are they? I honestly don't know so if you can educate me on this matter i would like to know.

My main reason for not keeping superfetch on is because it has no bonuses for me. The same for windows search. I don't have need of it and leaving it on just for the sake of it being on has no up side for me. Any service will consume resources and clock cycles so if I don't need it I disable it.
I do the same for lots of other services I have no use for.

In place of windows search try everything, completely blows it away and is so much faster.
http://www.voidtools.com/

I also like my work environment quiet sometimes. So when I am sitting reading something I hate to all of sudden have the hard drive start thrashing because windows feels it needs to do something like superfetch or drive indexing. I hate OS that take it upon themselves to do things that I did not tell it to do , be it updates, virus scans, or anything else.

 

[lxskllr]

I thought it was smart enough to know which ones were used most, that might mean that some of each of those games files were already loaded while the rest would not be (i assume you know what i'm talking about) which would mean that not all files would be pre-read if there isn't enough memory to do that, of course. In combination with readyboost that should really reduce wear and tear on the HDD by ... not enough to make it noticeable.

If you rebeoot your computer it would have to reread those files into superfetch, wouldn't it? Superfetch is gone from ram when rebooted so that might cause extra wear.

I don't think it matters either way either, i'm just trying to figure out whether superfetch and preload works in the same way.

All that's correct. What I implied by playing Bioshock was I haven't played it since release, so it would be a one off, and Windows would have no idea. I guess I need to type what I mean instead of assuming people can read my mind :^P