Ars Analysis Calls Windows 7 Memory Usage Claims "Scaremongering"

Via newsycombinator comes a reaction at Ars Technica to the recently reported claims of excessive memory use on machines running Windows 7. From the article: "I installed the XPnet performance monitoring tool and waited for it to upload my data to see what it might be complaining about. The cause of the problem was immediately apparent. It's no secret that Windows 7, just like Windows Vista before it, includes aggressive disk caching. The SuperFetch technology causes Windows to preload certain data if the OS detects that it is used regularly, even if there is no specific need for it at any given moment. Though SuperFetch is a little less aggressive in Windows 7, it will still use a substantial amount of memory—but with an important proviso. The OS will only use memory for cache when there is no other demand for that memory."

Comments

So

[sopssa]

Though SuperFetch is a little less aggressive in Windows 7, it will still use a substantial amount of memory—but with an important proviso. The OS will only use memory for cache when there is no other demand for that memory.

I really wonder when people will get this. In the earlier thread I saw people commenting that Windows 95 didn't need so much memory and so on..

To state it again. This is not RAM memory you need, use or have purpose for. IF you do need it, it is zeroed-out and free'd to application in like 30ms (one frame in usual FPS games).

If you have fast memory, do use it to it's full extend.

Re:So

[Dutch Gun]

More to the point, the company that wrote this little monitoring tool badly misunderstood basic principles of how the operating system works. At this point, I think we can move on and completely disregard any conclusion they came to. It either demonstrated profound ignorance or a deliberate attempt to mislead people it what turned out to be a slashvertisement of their products and company.

From the article:

One might almost think that this whole exercise was simply a cynical ploy. Allegations of Microsoft bloatware are, of course, nothing new, and oblique references to the old canard that what Intel gives, Microsoft takes away does nothing to dispel the impression that this is another case of Microsoft bashing.

What a surprise. Fortunately, people really didn't even let them get away with it even in the previous article. Microsoft deserves plenty of what slashdot slings its way, but let's stick try sticking to facts.

Re:So

[mystikkman]

You have no idea what you're talking about. Superfetch is much more than stats on commonly opened files. It takes into account the times of the day, weekends etc. too among other advanced stats. Anyway if it's trivial to roll your own, why doesn't such a thing run by default in Ubuntu? That's the thing that's sad and depressing, not giving names to technology.

Re:So

[Jah-Wren Ryel]

To state it again. This is not RAM memory you need, use or have purpose for. IF you do need it, it is zeroed-out and free'd to application in like 30ms (one frame in usual FPS games).

The problem with previous versions of windows (I haven't used anything newer than XP) is in how the OS decides that you do not "need, use or have a purpose for" certain types of memory.

The pathological, and yet all too common case with XP is the OS's decision that text pages should be dumped in favor of disk cache far too soon. The result being that if you have multiple apps open and a few that you haven't touched for roughly 10 minutes and then go to copy a couple of gigabytes of files around the text pages for those 'idle' applications are flushed out and the disk cache loaded with parts of those copied files (which you are unlikely to ever need). When you click on the iconbar to bring one of those formerly idle apps back to the foreground the system grinds away for a long time (obviously machine dependent but never instantly and frequently way beyond the point of annoying) as it reloads those text pages from disk before the application even starts to redraw itself much less starts becoming fully interactive again.

The worst part about that behavior is that, to the best of my knowledge, there are no knobs to tweak it. I can't specify how long a text page needs to be idle before it should be a candidate for flushing or even if it should be pinned down permanently so that is never paged out. I once went looking to see if there was a way to do it from within the application code itself - something like mlock()/mlockall() in posix - and I couldn't find an equivalent, which may just be a reflection of my own inexperience with the Windows API but I figured I would throw that out there anyway.

Re:So

[berboot]

SuperFetch also keeps track of what times of day that applications are used, which allows it to intelligently pre-load information that is expected to be used in the near future.
Source: Wikipedia
Their work, says Horvitz, was able to predict which applications users would open by time of day and also by day of the week.
Source: InfoWeek

Linux does that

[Animats]

Linux uses available memory for cache, and rather aggressively. All available memory can be filled with cached file blocks. This happens routinely on systems which have big randomly-accessed files open, like databases.

There's nothing wrong with this, except that, once in a while, Linux hits a race condition in prune_one_dentry, causing an "oops" crash, when there's an unblockable need for a memory page and something is locking the file block cache.

This is one of the Great Unsolved Mysteries of Linux. Linus wrote about it in 2001 ("I'll try to think about it some more, but I'd love to have more reports to go on to try to find a pattern.. "). As of 2009, this area is still giving trouble. The locking in this area is very complex.

Re:It's a matter of definitions

[Superdarion]

Windows 7 is sucking up your system memory to make Windows appear faster.

So windows has a feature which makes everything run faster and yet it only "makes Windows appear faster", instead of making it actually faster?

It seems to me that windows is only using hardware in a rather intelligent way: if it's not being otherwise used or needed, it uses it to boost performance.

Linux does the same thing, as far as I know, and you don't see anybody calling Linux a memory hogging OS.

This is one of those great mysteries of life

[davmoo]

if everyone is so afraid of their computer memory being used to the fullest, why do these people install so much of it?

I've got 8GB of ram in the machine I'm on at the moment, and I want the OS and applications to use it to the fullest and most efficient extent possible at all times. I didn't install a 64-bit OS and 8GB of ram so that I can see 6GB free at all times.