Do i need virtual memory enabled with 4gig of ram?

growse · 22 Apr 2007 at 17:44

This is getting a bit silly. Of course if you have 1TB of memory on a standard windows XP install you could probably get away without ever paging anything to disk, but at the same time you could install windows and all your apps into RAM anyway.

As has already been said, the whole point of a pagefile is to give the kernel somewhere to put memory pages that currently aren't very active, so they don't sit in physical RAM using up space that could be occupied by pages which are actually being used by processes.

Rebelius · 22 Apr 2007 at 17:45

saffyre said:
I dont see what you find so funny? You havent explained to me once the purpose of VM asside being a solution to having less ram than you need.

why would anyone want to spend over a grand on another 16GB or RAM when they could just enable 4GB of page file with no downside?

Final8y · 22 Apr 2007 at 17:47

saffyre said:
The other part of it?

You can have a bigger page file than real ram that can allow you to work on some files bigger than available ram.

saffyre · 22 Apr 2007 at 17:48

Sorry but the downside is the time spent reading/writing to disc.

Again, a soltion to not having enough ram. I know what im saying isnt viable atm but thats never what i have been trying to assertain.

Final8y · 22 Apr 2007 at 17:51

saffyre said:
Sorry but the downside is the time spent reading/writing to disc.

Again, a soltion to not having enough ram. I know what im saying isnt viable atm but thats never what i have been trying to assertain.

Well yes there is always a down side but for some things you will not notice the speed difference but at least it allowed you to do what you need to do.

saffyre · 22 Apr 2007 at 17:53

Yeah it had/has its purpose without a doubt.

NathanE · 22 Apr 2007 at 17:59

saffyre said:
Sorry but the downside is the time spent reading/writing to disc.

A small trade off of against a much larger disadvantage of running out of memory.

saffyre · 22 Apr 2007 at 18:23

Not being funny NathanE, but why do you keep re-iterating the fact that if you dont have enough real memory to do what u want then you need virtual memory. Im fully aware of that fact so please stop re-iterating it. You seem to totally ignore the fact that what ive been asking all along is that if your not going to run out of RAM do you need a page file.

Rebelius · 22 Apr 2007 at 18:24

my guess is yes, because there's no OS that doesn't expect you to ever run out of RAM

saffyre · 22 Apr 2007 at 18:34

I would imagine you would have the same results if you ran out of RAM (with no page file) as if you ran out of RAM and filled up your page file?

NathanE · 22 Apr 2007 at 19:47

saffyre said:
Not being funny NathanE, but why do you keep re-iterating the fact that if you dont have enough real memory to do what u want then you need virtual memory. Im fully aware of that fact so please stop re-iterating it. You seem to totally ignore the fact that what ive been asking all along is that if your not going to run out of RAM do you need a page file.

:/ The answer I've been giving all along is an uncategorical "yes".

There are operating systems out there that can run smoothly without a page file (as long as you don't run out of memory!!) but Windows isn't one of them.

|Ric| · 5 May 2007 at 14:11

Sorry for the thread revival but I was quite wanting some evidence of the claims in the thread

I think they were made by NathanE but if anyone has something to prove it, it would be nice:

Even when you turn the page file off in Windows it will make a temporary one anyway

Also any benchmarks to show that when running 4gig (or even 2gigs) it is faster to have paging turned on?

Energize · 5 May 2007 at 15:31

Rebelius said:
why would anyone want to spend over a grand on another 16GB or RAM when they could just enable 4GB of page file with no downside?

You can get 16GB of ddr2 667 ram for £408.84 inc del actually.

One downside would be that 'huge' 4GB less of hdd space.

ROfu · 5 May 2007 at 20:42

ok i though id throw in a few questions.

16gb of ddr 667? for 400bux?
obviously 16gb would have to be ECC memory .. as theres no normal consumer boards (only server/workstation) that support that much ram.
so Irrelevant to how much you can buy.. it couldnt be used.

|Ric|, if you want to see what windows does without pagefile, and what files it produces on the fly. turn off yours load up a lot of applications and see what happens. Pagefile.sys i think the file your looking for. it should be in the root of the C: drive if you turn it off.. although it might be kept in the temp folder.

Windows has been a virtual memory based OS for many years so turning it off is pointless and wont make your system use more system ram, as most background apps and bought apps are built to use a certain amount of pagefile for low priority addresses.

Obviously the more Physical ram you have installed the better (although going over 4gb on a 32bit OS is a little pointless unless you open lots of large apps at once - on 64bit OS then the more memory the better) But the amount of physical ram shouldnt change the fact that you NEED pagefile on Windows and Linux is built with it in mind as well (although can be configured to be less reliant).

As a final point 4gb of pagefile doesnt equate in anyway to 16gb of physical ram, i'm sure this wasnt meant as a direct comparison - more as over emphasising a point, But remember in most OS's Physical ram and Pagefile are used as seperate entities in most current applications.

Cheers
ROfu

Energize · 5 May 2007 at 20:57

Technically you could buy an i-ram module or similar to fit upto another 8gig of ram per pci-slot and put the pagefile on that to speed things up, and not use the hdd. Hell with 16gb you could install the whole os on it.

|Ric| · 5 May 2007 at 20:58

Well I am currently running with "no paging" and there is no obvious page file on any hard drive.
I have 1.5gigs of ram and had a 1.5gig page file before. Before dxdiag was reporting a page file of 3gig and now it is reporting one of 1.5gig, I assume that it includes the amount of physical ram in its calculation unless windows is hiding a 1.5 gig page file from me!

The main reason for my curiosity is some people that know an awful lot more about the inner workings of XP at university have told me when you have 2 gigs of physical ram you get best performance from turning off the page file.
So it would be nice to have some evidence that windows still uses a temporary page file rather than just a don's word.

NathanE · 5 May 2007 at 21:20

Yeah now load up some of the biggest applications you may have installed and then load up a big game (I hear Battlefield 2 is one of the biggest). Watch your system crash from "out of memory" errors

If you turn the page file off, Windows creates a temporary one just for kernel mode software i.e. device drivers. Otherwise the system would blue screen when memory was tight.

PS: Those students must still be in 101 classes because they obviously haven't been taught about Operating Systems yet which is usually a 2nd or 3rd year course...

Burnsy2023 · 5 May 2007 at 21:50

|Ric| said:
The main reason for my curiosity is some people that know an awful lot more about the inner workings of XP at university have told me when you have 2 gigs of physical ram you get best performance from turning off the page file.

What uni are you at because I know several techy guys at Southampton Uni who would have a good laugh at that.

Burnsy

ROfu · 5 May 2007 at 22:16

Energize - sadly you can only put upto 4gb per I-ram pci card, as im using one for exactly what you suggested.. i use mine for pagefile, and yes it does speed up things, not massively but when you hit the limit of your physical ram and a large chunk of pagefile gets used, then there is a noticable speed bump to a HDD.

But this is covered on another thread

|Ric| - i understand if you have folks telling you how things work in university, now im hopeing the folks your talking about arent lecturers, and just college buddies or classmates. Like a few of us have mentioned in previous posts - if the people giving you this information are so sure about themselves.. get them to show you directly, as your in Uni with them, get them to put thier money where thier mouth is in the flesh, as all we could supply at best are screen grabs, which could easily be doctored if anyone was that way inclined.

Like NathanE mentioned load up either battlefield 2 or battlefield 2142 (they both run off the same base game engine) as these two games use silly amount of ram needlessly, but are great examples to test the "you only need 2gb of ram and no pagefile" theory. If you have a version of Maya available (you can download a educational copy for free) and create a few hundred thousand cubes, this will also give you the same result.

Its very easy to question the words of a forum poster compared to a person you spoke to in the flesh, But you should consider exploring thier theories with them first hand before making judgements - which is what Uni is all about .. working out whats worth learning

Cheers
ROfu

|Ric| · 5 May 2007 at 22:19

I can't narrow it down to the specific person because I got told it via my tutor in a supervision, but it came from an employee at a spin off from the computer lab that is fiddling around with virtualisation.

Granted as this is second hand something could have got missed out and I'm sure that they were talking more about a work environment than games. But arguably photoshop has to be up there as one of the big ram hogs.

Incidentally OSs is taught in the first year and I've done it so I am aware of the general principles of virtual memory but we never looked at this specific issue when looking at NT.

I don't quite understand your remark about the temporary page file as it seems unnecessary, if an out of memory exception is triggered then what ever caused it is arguably useless so kick it out and load in anything needed by the kernel. But I don't see why this would not already be in RAM any way?