wierd ram/pagefiling thingy.

[Dak]

OK, I just replaced my 64MB ram card with a 512MB one, thus taking my total ram from 192MB up to 638MB... quite a difference, and my computer seems alot zippier as a result.

 

However, I notice that the pagefile is still being used as much as it was before the upgrade.

 

Curoiouse, I turned pagefiling off and rebooted, only to find the page file STILL being used as much as it was before...

 

So, does anyone know why, with all the extra juicy ram, the taskmanager still shows between 200 and 300MB of my page file being used? espescially when pagefiling was turned off?

[insane_alien]

I thought both RAM cards had to be the same size/type otherwise it got screwy possibly giving the effects you describe.

[1veedo]

No. I've heard that before but I think that's the way old motherboards wanted you to do it. My old 97 computer used to complain if I had two different sized RAM cards but I updated the BIOS and now it works just fine.

 

I'm not sure why it'd be using more pagefile. Pagefile is the same thing as swap, right? Chances are you're just overreacting. I have 512MB here and it says 173 is being used. 298MB of swap (out of 1G) is being used even though it could easily fit it all in RAM. But pagefile / swap isnt some sort of replacement for RAM. It's not like it's an issue of the HD being slower or anything. Some programs use swap space anyway, reguardless of how much RAM you have. Some programs will also refuse to use swap space. It's just how it's programmed. The kernel wont just move around memory 'cause you have more space now.

 

Chances are your pagefile is the same size because you're still running the same programs.

[5614]

I see what you mean, what used to be on the PF (page file) should now be on the RAM.

 

And you say you totaly removed the RAM file?

control panel > system > advanced tab > performance (settings) > advanced tab > virtual memory (settings)

did you select 'No PF'?

 

Maybe some software (ie. windows stuff) always uses the PF. I have 1GB of RAM and my PF is always ~300MB.

 

=====

 

And as for the RAM thing, they do not have to be the same size (ie. 256MB) but they do have to be compatable with the motherboard (mobo). So if you currently have a PC3200 RAM stick then, well, it used to be that your mobo was only compatable with another PC3200, however now-a-days mobos are often compatable with multiple speeds, so sometimes you could mix and match, a bit. But RAM speeds will (I'm not certain but pretty sure) be limited by the slower one, so there is little point getting one RAM stick faster than your current one (assuming you are adding them together). If you are replacing one with a new one then all you need to do is ensure it's compatable with the mobo.

[1veedo]

I see what you mean, what used to be on the PF (page file) should now be on the RAM.

Sometimes it's better to use the HD instead of RAM. Hense you saying,

Maybe some software (ie. windows stuff) always uses the PF. I have 1GB of RAM and my PF is always ~300MB.

Just because he has more RAM doesnt mean the page file will be used less.

[Sayonara]

I thought both RAM cards had to be the same size/type otherwise it got screwy possibly giving the effects you describe.

They need to be the same speed, or ALL the memory is clocked down to the speed of the lowest rated stick. Iirc it may also cause rapid "aging" of the memory itself. On motherboards that support dual-channel ram, paired sticks ought to be identical in order to avoid problems.

 

With reference to the o/p, increasing the RAM available in your machine is unlikely to have a significant effect on pagefile usage.

[5614]

What program always uses the PF even if there is sufficient RAM? And why? It is quicker to use the RAM, why would the computer revert to using the PF unless the RAM was running low (which it isn't).

[Dak]

I thought both RAM cards had to be the same size/type otherwise it got screwy possibly giving the effects you describe.

 

In addition to what sayo said: SIMMS require same sized ram sticks, but with DIMMS (which is what i have), you can mix two ram sticks of different size.

 

...a PC3200 RAM stick...

Lol, I feel behind the times... I have two PC133 sticks.

[Sayonara]

What program always uses the PF even if there is sufficient RAM? And why? It is quicker to use the RAM, why would the computer revert to using the PF unless the RAM was running low (which it isn't).

If the operating system is to keep running vital services, it has to have swap space. If that swap space is the system memory, then every time any program needs to use the memory, the current use and expected use needs to be evaluated, information moved out of the memory and saved to disc, then it has to be moved back when the memory is freed, and all of this is at least doubling bus usage and reducing memory throughput available to the whole system.

 

Errr... I think.

[5614]

But what you're saying doesn't 100% agree with the pagefile always being (for me) about 300MB

 

Slightly modifying your answer to make it fit the observation:

 

The OS needs memory space which is stores in the PF so that if other programs are opened then there is sufficient RAM for them to use. Basically the OS stays in the background giving more memory for running programs.

 

So I removed the "it has to be moved back when the memory is freed" part because if that were true then at certain points the PF would become empty as all of the OS's memory was transferred to the RAM.

 

Or have I misinterpreted you?

And are you just logically guessing or do you know?

[Dak]

I asked a computer techy guy, and he said that what the task manager reports as 'page file useage history' is actually virtual memory useage.

 

Virtual memory = ram + pagefile, so... i wasn't using about 250MB of pagefile, i was using about 250 MB of memory, which was more than likely all on my RAM.

 

If the operating system is to keep running vital services' date=' it has to have swap space. If that swap space is the system memory, then every time any program needs to use the memory, the current use and expected use needs to be evaluated, information moved out of the memory and saved to disc, then it has to be moved back when the memory is freed, and all of this is at least doubling bus usage and reducing memory throughput available to the whole system.

 

Errr... I think.[/quote']

 

That's how a swap/page file works, but it doesn't actually NEED it, as such, aslong as you have sufficient RAM (at least, as far as i know).

 

Speaking of evaluating expected use:

 

...when programs ask for an allocation of Virtual memory space, they may ask for a great deal more than they ever actually bring into use — the total may easily run to hundreds of megabytes. These addresses have to be assigned to somewhere by the system. If there is a page file available, the system can assign them to it — if there is not, they have to be assigned to RAM, locking it out from any actual use.

 

from http://aumha.org/win5/a/xpvm.php

 

So, even if my pagefile is being 'used', it might not be. if that makes sence.

[5614]

That does make sense.

 

it doesn't actually NEED it, as such, aslong as you have sufficient RAM (at least, as far as i know).

That is correct, the page file is there to act as a life saver if the RAM runs low or out of free space.

[1veedo]

No, Sayonara³ is right. I'm telling you, right now, 149 / 512MB is being used as RAM. My swap is 241 (out of a gig). I have like 15 text files open of programming in Kwrite and I'm maximizing them, right now.

 

RAM just jumped to 190. SWAP stayed the same, but this is just because stuff in SWAP doesnt need to be removed (it's just lyign on the HD).

 

After minimizing them RAM went back down to 148. Now I'm going to close ALL of them. The SWAP dropped to 208.

 

Obviously if computers were in the buisness of putting everything it possibly could into RAM it could do that.

 

208+148 is 356. Instead, by removing stuf from RAM, it speeds everything up . This is why when you restore things after they've been minimized for a while (Firefox, documents...pretty much anything), it'll take a second to load before you can start playign with it. This is because everything on the SWAP is being loaded into RAM. It takes maybe half a second (actually, on Windows it takes forever) but I'm sure you've noticed it before. The time it takes something to become inactive depends on the program. Kwrite does this automatically. You can minimize firefox and leave it for a while before it does it.

 

SWAP and RAM are NOT the same thing. They are NOT interchangeable. Each servs it's own purpose. SWAP is there to speed things up, not to some how store "overflow" when the demand for RAM gets too big.

 

 

(it jumped after opening ksnapshot)

[Sayonara]

If you have substantially more RAM memory than is ever used by the pagefile, then theoretically you don't "need" to use the hard disc. But just because the data stored in the pagefile can fit in the RAM, doesn't mean it's the best place for it. That's what I was trying to explain.

 

Although I'm fairly confident Windows will lie a lot anyway.

[5614]

I have sufficient RAM to store all of the RAM + PF on the RAM.

 

RAM is faster than using the page or swap file.

 

So therefore would it speed my computer up to disable the PF and therefore force everything onto the RAM?

[Sayonara]

I know a way to find out.

[Dak]

mmm... empirical evidence.

 

I can notice no difference between page filing being on and page filing being off, with a RAM:used memory ratio of 1.5:1.

 

Note that i have no idea exactly what windows means when it says 'total used virtual memory'.

[Klaynos]

Note that i have no idea exactly what windows means when it says 'total used virtual memory'.

 

The answers not much, and certainly not the full story

[1veedo]

It speeds up the RAM, ie programs run faster, when there's less stuff in RAM. Sometimes the HD is the best place for things. At least "technically." I dont think it really slows you down that much until you're using a large percentage of it. There are a couple reasons for this, mainly (I think), your CPU has to work harder.

 

I read someware that you can control if certain programs are allowed to use SWAP. or tell it to never use SWAP. The advantage is that programs never go dorment(and thus you dont have to wait half a second after you restore it). Some things do need swap though. Like when you're watching a video. Your video player will use SWAP to buffer (parts of) the media and load it to RAM a few miliseconds before it needs to be played.

 

Mostly though it's pretty useless. I guess having SWAP would allow you to calculate pie to more digets.

[5614]

Agreed. I think for most home computing 512MB (and certainly 1024MB) is sufficient RAM that you don't really need a page file. Even serious gaming isn't likely to take up all of the 1024MB of RAM.

 

I spose if you are doing a lot of rendering and high quality professional work with images then you could use it. So for example 3D Studio Max 7 (professional computer animation software) suggests you have 1GB of RAM and a 2GB page file.