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

saffyre · 22 Apr 2007 at 16:35

OK thats fair, but say I have 4gb of memory, then i can have 4gb of programs open before it asks me to close some programs?? As apposed to someone with 1gb of ram and a 1gb page file who can have 2gb of programs open.

Sorry if i seem argumentative im just trying to get a good view of the purpose of virtual memory.

It seems to me that when deciding if you really need a page file or not you should look and see how much memory you are likely to use, if your memory requirement exceeds the amount of available system memory you have then you need virtual memory. If you will never have >4gb of memory usage then with 4gb of memory you dont really need a page file. I dont think its a matter of you need as much page file as you have ram. As far as i can see you need as much virtual memory as you need memory for the program that you intend to run.

Or would you rather have a problem that the Os wanted to move 2GB of mem content to pagefile for whatever reason but could not because you only gave it 1GB pagefile & popup & say you need to close some apps.

That problem could arise no matter how much pagefile you have. You could just keep opening more apps until you have no virtual memory left.

Edit: As a silly but good example i think, say i have an XP machine with 1 terrabyte of memory, should i have a 1 terrabyte page file?

NathanE · 22 Apr 2007 at 16:45

saffyre said:
As a silly but good example i think, say i have an XP machine with 1 terrabyte of memory, should i have a 1 terrabyte page file?

Yes. There should always be a 1:1 (as a minimum) ratio between the size of physical memory and the page file. Anything less and you put the memory manager under more stress.

Final8y · 22 Apr 2007 at 16:48

saffyre said:
OK thats fair, but say I have 4gb of memory, then i can have 4gb of programs open before it asks me to close some programs?? As apposed to someone with 1gb of ram and a 1gb page file who can have 2gb of programs open.

Sorry if i seem argumentative im just trying to get a good view of the purpose of virtual memory.

It seems to me that when deciding if you really need a page file or not you should look and see how much memory you are likely to use, if your memory requirement exceeds the amount of available system memory you have then you need virtual memory. If you will never have >4gb of memory usage then with 4gb of memory you dont really need a page file. I dont think its a matter of you need as much page file as you have ram. As far as i can see you need as much virtual memory as you need memory for the program that you intend to run.

That problem could arise no matter how much pagefile you have. You could just keep opening more apps until you have no virtual memory left.

Well of course you can run out if you keep running more apps, but if you think your never going to need 4GB of ram then you would not have it installed in the first place.
And once again your ignoring what has been posted as you say you dont need a page file if you have x amount of ram when its not as simple as that as the Os has been made with the pagefile in mind & its not just there to use when real memory gets tight & you could end up slowing down OS performance.

saffyre · 22 Apr 2007 at 16:48

That seems crazy, I would never even use close to 1tb of memory why would I need a page file?

Final8y · 22 Apr 2007 at 16:50

saffyre said:
That seems crazy, I would never even use close to 1tb of memory why would I need a page file?

I have used 3987MB

saffyre · 22 Apr 2007 at 16:52

Final8y said:
Well of course you can run out if you keep running more apps, but if you think your never going to need 4GB of ram then you would not have it installed in the first place.
And once again your ignoring what has been posted as you say you dont need a page file if you have x amount of ram when its not as simple as that as the Os has been made with the pagefile in mind & its not just there to use when real memory gets tight & you could end up slowing down OS performance.

Please tell me what other purpose the page file has? Then i may understand your reasoning.

I think its perfectly viable that somone may buy 4gb of ram so they naver have to use a page file. After all if your having to backup process pages to disc and then read them back when you need them then your loosing performance..

Edit. 4gb < 1000gb

Final8y · 22 Apr 2007 at 16:52

Also if it was not for the pagefile your ram usage would go up.

saffyre · 22 Apr 2007 at 16:54

Thats good though, both linux and vista use memory managers which try and use as much ram as possible. After all free ram is essentially wasted ram.

Final8y · 22 Apr 2007 at 16:59

saffyre said:
Please tell me what other purpose the page file has? Then i may understand your reasoning.

I think its perfectly viable that somone may buy 4gb of ram so they naver have to use the page file. After all if your having to backup process pages to disc and then read them back when you need them then your loosing performance..

Edit. 4gb < 1000gb

As already been said that you can not turn page file fully off so the Os has to work harder in sorting out what it is going to write to disk as you have given it less leeway.

There are also processes that are not speed critical that would be in ram needlessly.

saffyre · 22 Apr 2007 at 17:03

Im pretty sure you can run linux without a swap file. If you have enough free ram then why do you need to waste time writing to disc?

Edit: it seems to me that the way windows XP manages a page file is on this assumption. The user has 1gb of ram in his machine therefore he expects to use 1gb of ram frequently therefore I should have at least a 1gb page file. This is fair enough if a user expects to use all that ram. However if i buy 1tb of ram and never expect to use it then this assumption would be invalid, and as such so would be the page file allocation.

NathanE · 22 Apr 2007 at 17:10

If you do that then it won't be usable as a desktop OS anymore. 4GB will be easily used up. I have 59 processes running and they are using around 5GB of memory in total. However only around 1GB of that is currently in physical memory.

Swapping pages out to the page file doesn't hurt performance because the pages were idle anyway. It's when you come to bring them back into memory that there is a small hit but that hit is negligable because if it was an important page it would have been in physical memory already...

saffyre · 22 Apr 2007 at 17:12

Agreed NathanE. That comes down to the way the OS manages its pages. However if you have 20gb of memory in your system wouldnt you rather all of that 5gb of data was kept in memory ready to be used?

NathanE · 22 Apr 2007 at 17:15

I can't answer that because that day will never come.

Typical memory capacities and software requirements will always be roughly in sync with each other.

Final8y · 22 Apr 2007 at 17:18

saffyre said:
Agreed NathanE. That comes down to the way the OS manages its pages. However if you have 20gb of memory in your system wouldnt you rather all of that 5gb of data was kept in memory ready to be used?

LOL i was waiting for that one

saffyre · 22 Apr 2007 at 17:23

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.

Final8y · 22 Apr 2007 at 17:23

NathanE said:
I can't answer that because that day will never come.

Typical memory capacities and software requirements will always be roughly in sync with each other.

Yep & with good reason, they need you to keep buying memory from them as much as they can make you.
Giving you too much now means a long wait for them untill you buy again.

Final8y · 22 Apr 2007 at 17:29

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.

A big part of it is exactly that.
a lot of people find it hard to afford ram 2-4GBs of ram until lately & if it was not for the page file in the first place then even with windows XP minimum required ram would be at least 1.5-2GBs.

NathanE · 22 Apr 2007 at 17:33

Final8y said:
Yep & with good reason, they need you to keep buying memory from them as much as they can make you.
Giving you too much now means a long wait for them untill you buy again.

There's not really any conspiracy. It's just the way a free market economy works...

Also virtual memory lowers the memory requirements by several magnitudes which is why it exists and why it is stupid to turn it off or impede it in anyway.

saffyre · 22 Apr 2007 at 17:34

The other part of it?

Final8y · 22 Apr 2007 at 17:42

NathanE said:
There's not really any conspiracy . It's just the way a free market economy works...

Also virtual memory lowers the memory requirements by several magnitudes which is why it exists and why it is stupid to turn it off or impede it in anyway.

I would never think of turning off pagefile as i have been to my ram limit far to often & would not like have to close what i was doing on the other monitor because i wanting a tad more maybe unnoticeable speed up by turn it off.

Yes there is no conspiracy but it sure can look like it at times

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