4GB of Ram - Yet usage is only around 1gb and page file is still used...

[Snookieboy]

Hey,

I got myself another 2gb ddr2 ram for my PC in hoping it would stop Vista ever using a page file on the hard drive in the idea things would speed up even more (and for the ability to multitask over dual monitors and eventually quad monitors)

One thing I noticed now with Vista is that the ram usage is usually around 1000mb-1200mb yet looking in Task Manager the page file shows as 1700mb / 8400 mb which I assume means its using 1.7gb of a total available 8.4gb.

What I dont get is why if theres 3gb of ram currently available, why does it even bother using the page file when theres tons of ram available for it to use?

Is there any tweaks or ways to make Windows effectivly use the ram available to it?

[kalniel]

Vista precaches into RAM. This is a good thing.

[dave87]

What Kalniel said.

Otherwise try turning off the pagefile, see what affect that has on system performance/memory usage..

[Snookieboy]

Originally Posted by kalniel

Vista precaches into RAM. This is a good thing.

Sorry for asking this, but what exactly do you mean by this?

Forgive me for asking this if its something simple and easy, I just dont understand

[Moby-Dick]

Pagefiles isn't always a bad thing - the server I run use 10Gb + memory and still run a page file of the recommended 1.5 phys memory size

[Funkstar]

As i understand it, Windows sends stuff out to page file that it doesn't need, but has to keep loaded. This means there is more physical ram for things that do need it and for dynamic caching. This cache won't appear in Task Manager.

Apparently Vista is far more aggressive in the amount of memory it uses for caching. It basically tries to use every last piece of memory it can get it's grubby little hands on. The memory manager it pretty sophisticated so it will decide it is more important to cache a certain block of data than to have this other piece of data in memory. It can't unload that other data, so it sends it to the page file.

perhaps that is over simplifying things, but as i said, that's how i understand it. If anyone else has a better (or indeed more accurate) description, then feel free to correct me

[LordOfLA]

Last I read from a reliable source was that windows will page. Period. No matter what you try and do to stop it.

Best bet is to have 1.5 times physical ram as swap or just tell vista to manage it and be done with it. Paging isn't going to kill you on a system with 2+GB ram.

Edit: Since I don't meet the requirement for posting urls. Head over to OSNN.net and click articles on the main menu, then guides, and understanding virtual memory.

[aidanjt]

Windows has always needlessly paged memory, this is nothing new, drop the pagefile size and you'll force it to keep things in ram.

[LordOfLA]

I don't think its needless. It'd be somewhat akin to carrying your bookshelf everywhere because you might need a book sometime and calling people who leave their bookshelves at home silly.

Why keep unused data in ram when that ram could be available for disk caching or active foreground applications like games or other such ram intensive applications?

[LordOfLA]

Oh and it's just occured to me that XP users complain about XP keeping data out of RAM and then complaining that Vista keeps too much data in ram.... Hypocritical I think

[kalniel]

Originally Posted by LordOfLA

Oh and it's just occured to me that XP users complain about XP keeping data out of RAM and then complaining that Vista keeps too much data in ram.... Hypocritical I think

Not really - people complain that XP pages to the hard drive, and the complaint here about Vista is that it's also putting data in the pagefile in the hard drive.

Funkster explains pre-caching pretty well. Basically the idea is that it's so quick to flush data from RAM you might as well fill it with things you might need, because loading things from the hard drive into RAM isn't as quick. If you need to put something else into RAM that isn't there then you just flush as much room as you need. Linux has been using a similar system for years.

Regarding page files, first thing to note is that 'page file usage' under task manager isn't quite accurate (under xp at least) - it's reporting the window of accessible memory that's being used - so this includes physical RAM as well. Actually separating out usage of the virtual memory on the hard drive is trickier. Secondly windows will always have some files paged to the hard drive - in Vista's case stuff it thinks it won't need immediately, but still wants to cache because it's quicker than searching the hard drive for the file.

What does this mean? Well because XP doesn't have this pre-caching ability (to the same extent at least) it tends to think stuff that's in RAM needs to stay in RAM, and it's a bit paranoid about keeping space in physical RAM so can be a bit virtual memory happy. There are some simple registry tweaks to adjust this behavior and indeed it's usually quite happy running without a specified page file as well. Now Vista with it's pre-caching has a different philosophy - flood the physical RAM and maybe use a bit of page file as well. However the consequences of doing so are not negative in Vista, as it's quite happy to chuck stuff out of physical RAM to make room for what you are running. End result - more stuff you're running will be running from physical RAM, and less stuff will need to be loaded up from the hard drive.