Please help me with Windows XP 32-bit

[happita]

Ok. I know that XP 32-bit cannot fully utilize 4GB of ram, but my cousin is soooooo convinced that it can handle like 8GB or more. I'm not exactly sure WHY XP can't use all of it, so I would like for you TPU Gurus to tell me why, so that I can shut his mouth up. Oh, in response to my email I sent him, he told me to look at the microsoft link he provided concerning memory addressing.

http://msdn2.microsoft.com/en-us/library/aa366778.aspx#physical_memory_limits_windows_xp

 

[happita]

This is the email he sent back to me...take a look.

"listen dude, my mistake for even writing the email in the first place...you simply wont accept being wrong or taking any advice....there is no sense in telling you anything, you will not ever believe anything any one of us ever says. lets see what microsoft says.

http://msdn2.microsoft.com/en-us/library/aa366778.aspx#physical_memory_limits_windows_xp

Enough arguing?"

 

[Disparia]

So... he gave you a link that proves himself wrong? I don't think there's any help for him

 

[xfire]

If your cousin wants to waste money let him waste. Some times people just don't listen. When he realises he made a mistake he'll see it then. Also you can ask him to show a single file thats greater than 3Gb(other than video's).
Doesn't the link prove your point?
Let him learn the hard way.Or try telling it to some one he'll listen to so that they can tell him. Or tell him to call up M$.

 

[happita]

I'm looking for something real specific. From that site, I don't know how to interpret it. I just need reasons why XP won't address it all. From what pieces I can remember, people have said that if 4GB is put in xp 32-bit, it takes some memory and uses it for the video card, some for the cpu, and some for page viewing file? Please correct me if I'm wrong.

 

[Disparia]

There are only so many addresses to go around in a 32bit system.

Understanding Address Spaces and the 4GB Limit"
http://www.hardforum.com/showthread.php?t=1035670

Also, if you cousin brings up PAE, you can tell him that it doesn't make a difference as far as XP is concerned. It's just there for DEP support.

 

[trog100]

out of curiosity.. i have 4 gigs of physical memory (ram).. windows used "virtual" memory.. in essence windows gives me 8 gig of "virtual" memory by default.. it creates a 4 gig pagefile on the hardrive..

to windows its all memory to be used as required.. so how does it cope with 8 gigs virtual if i can only address 4 gig in total..

in fact.. can it even use the extra 4 gig swopfile it creates.. i wonder.. ???

trog

 

[Darknova]

out of curiosity.. i have 4 gigs of physical memory (ram).. windows used "virtual" memory.. in essence windows gives me 8 gig of "virtual" memory by default.. it creates a 4 gig pagefile on the hardrive..

to windows its all memory to be used as required.. so how does it cope with 8 gigs virtual if i can only address 4 gig in total..

in fact.. can it even use the extra 4 gig swopfile it creates.. i wonder.. ???

trog

Of course it can. A Swapfile is just a dumping ground for the stuff that's not used that often. System memory keeps everything that needs to be used ASAP.

The physical limit that any 32-bit OS can address is 4Gb of system memory in TOTAL. Even with PAE it won't actually use more than 4Gb. Certain parts of the 32-bit register are reserved for all your PCI-E/PCI add-on cards, so depending on what graphics card etc. you are using, even with 4Gb install, XP may only see as little as 3Gb. All PAE does is get rid of that reserved spot, which can cause problems in a desktop OS.

64-bit OS's can deal with much larger amounts of memory, and as such, even with the reserved memory, the OS will still see the full amount of system memory you have installed.

Hope that's clear enough.

 

[trog100]

Of course it can. A Swapfile is just a dumping ground for the stuff that's not used that often. System memory keeps everything that needs to be used ASAP.

The physical limit that any 32-bit OS can address is 4Gb of system memory in TOTAL. Even with PAE it won't actually use more than 4Gb. Certain parts of the 32-bit register are reserved for all your PCI-E/PCI add-on cards, so depending on what graphics card etc. you are using, even with 4Gb install, XP may only see as little as 3Gb. All PAE does is get rid of that reserved spot, which can cause problems in a desktop OS.

64-bit OS's can deal with much larger amounts of memory, and as such, even with the reserved memory, the OS will still see the full amount of system memory you have installed.

Hope that's clear enough.

well u might think that i dont.. virtual memory is what windows uses.. part of it isnt simply a dumping ground for what dont get used often.. i recon u are wrong..

but aint gonna argue the point.. past experience tells me it aint worth it..

trog

 

[Darknova]

well u might think that i dont.. virtual memory is what windows uses.. part of it isnt simply a dumping ground for what dont get used often.. i recon u are wrong..

but aint gonna argue the point.. past experience tells me it aint worth it..

trog

Thing is, if that were true, you wouldn't be able to set a pagefile any larger than your system RAM + whatever to make it up to 4Gb, but you can. Try it for yourself.

If you set your pagefile to say, 6Gb, and you still only see 3.25Gb of virtual memory then I was wrong.

 

[trog100]

Thing is, if that were true, you wouldn't be able to set a pagefile any larger than your system RAM + whatever to make it up to 4Gb, but you can. Try it for yourself.

If you set your pagefile to say, 6Gb, and you still only see 3.25Gb of virtual memory then I was wrong.

the pagefile is supposed to grow as big as needed.. which kinda leads me to wondering.. what happens when i fill up all my 4 gigs of ram.. can windows still use the hardrive part of its virtual memory to go above the 4 gig limit.. ???

hard to use that much memory but i can try loading six games just to see what happens when the 4 gigs fills up.. he he he

trog

 

[Darknova]

the pagefile is supposed to grow as big as needed.. which kinda leads me to wondering.. what happens when i fill up all my 4 gigs of ram.. can window still use the hardrive part of its virtual memory to go above the 4 gig limit.. ???

hard to use that much memory but i can try loading six games just to see what happens when the 4 gigs fills up.. he he he

trog

That all depends on whether you have your pagefile set to dynamic or static. I personally set it to static, I have a 1Gb pagefile and 2Gb of RAM, if you set it to dynamic Windows only uses as much as needed, but does come at the price of performance.

 

[hat]

I thought you could use more than 4GB in Windows XP 32-bit with a simple command line switch in the boot.ini? /pae

 

[Darknova]

I thought you could use more than 4GB in Windows XP 32-bit with a simple command line switch in the boot.ini? /pae

Only on Intel chips, and even then there's a massive debate as to whether or not it actually does anything to help performance on a non-server OS.

 

[trog100]

the pae switch dosnt seem to do anything.. i have it set..

but to answer my wonderings.. can XP 32 use its swopfile when things go over 4 gig.. yes it can.. so it can have more than 4 gig of virtual memory even thow it only sees 3.5 gig of ram..

six games loaded.. in fact they are still loaded.. my machine is now swopfiling.. it now does not have enough real memory for what i am doing.. not exactly sprightly.. but it still works..

one cpu core seems to be going flat out the other doing nothing much..

trog

 

[Darknova]

the pae switch dosnt seem to do anything.. i have it set..

but to answer my wonderings.. can XP 32 use its swopfile when things go over 4 gig.. yes it can.. so it can have more than 4 gig of virtual memory even thow it only sees 3.5 gig of ram..

six games loaded.. in fact they are still loaded.. my machine is now swopfiling.. it now does not have enough real memory for what i am doing.. not exactly sprightly.. but it still works..

trog

So Windows does see the pagefile and system RAM as 2 separate entities, interesting.

 

[trog100]

and just to continue playing silly buggers.. having forget to turn off the odd thing running in the background.. errr six top end games.. here is super pi to 1 million.. 13.891..

basically windows simply starts to use its swopfile when it runs out of the real stuff.. with enough real stuff it never uses it.. with four gigs i could turn mine off without any problems.. but being as it in normal circumstances it never uses it turning it off dosnt gain anything..

trog

ps.. just for the record if i tab a game back into full screen its still quite playable.. serouse sam buzzes along without a care in the world oblivious to the other five games running in the background.. ..

 

[trog100]

so whats to be learned from my silly test..

it takes an awful lot of effort to actually use 4 gig of memory in XP.. 2 gig seems plenty..

u dont need a quad core to multitask.. my super pi score kinda proves that one..

i probably have more cpu power and memory than i can effectively make use of..

the original fear game took up 1.3 gig of memory.. the other five games only took up another 3 gig in total.. most games dont need as much memory as folks think they do.. fear seems to use double what anything else does.. even supreme commander only takes up about 600 meg..

dunno what else..???

trog

 

[Darknova]

Lol well that was interesting at least. Although you really shouldn't turn your pagefile off, there are certain programs that have a fit if you don't have a pagefile, not sure why though. always best to have at least 512Mb of pagefile.

 

[trog100]

Lol well that was interesting at least. Although you really shouldn't turn your pagefile off, there are certain programs that have a fit if you don't have a pagefile, not sure why though. always best to have at least 512Mb of pagefile.

i tried that back when i first had two gig.. i have read that some apps look for one.. but i dont have any that do.. everything worked okay without one.. it never even blue screened when i deliberately pushed it past 2 gig.. it just came up with a polite message telling me i didnt have enough memory to load the application and stopped trying to load it.. all very civilized.. he he

with 4 gigs it would have just refused to load the fifth or sixth game with no pagefile..

to prove to disbelievers that windows never used its swopfile unless it runs out of ram.. i also set it as small as i possible could.. basically if it uses a very small one the actual pagefile.sys will grow in size and stay at the expanded size.. i cant remember exactly how small it lets u go but its a pretty small 50 meg or so..

the super pi score with all that lot running did kinda surprize me thow. it pulls 11.235 with just normal stuff running at 4 gig.. a loss of only about 2 seconds with six games running seems amazing..

trog

ps.. i now leave the swopfile set at 2 gig minimum.. there is no point in turning it off.. it never gets used and simply wastes hardrive space.. i have plenty of that thow..

 

[Graogrim]

To answer the original question, any system employing 32-bit addressing will face a theoretical limit of 2^32 (or 4,294,967,296) distinct addressable memory locations. Since the addressing granularity for PCs is one byte, that means a limit of four gigabytes. Typically some of this space is reserved for other purposes, such as mapping onto hardware registers, leaving less RAM functionally accessible. So most users with 4 gigabytes installed will see approximately 3.5 of that available.

Your cousin might be misunderstanding the distinction between physical and virtual memory. Even plain vanilla 32-bit Windows XP running on a plain-vanilla 32-bit CPU can access very large sums of virtual memory. Although an individual pagefile in such cases is limited to 4095 MB, it's possible to employ multiple pagefiles to achieve the necessary total. The PAE switch can also be employed to ease size restrictions if a CPU with the necessary support is installed.

Microsoft's own support can provide some insight into how this can be made to happen.

So Windows does see the pagefile and system RAM as 2 separate entities, interesting.

Well, there are multiple layers involved here. On the physical level, Windows (really any OS that uses virtual memory) will see the pagefile and physical RAM as the distinct entities that they are, because it has to manage the transfer of data between the two. But the virtualized space they form when united is treated as all the same thing from an application's perspective, with the main distinction being whether or not accessing a particular virtual address triggers a page fault. If it does, that means either the address is invalid or that it resides in secondary storage and requires loading into physical memory in order for access to proceed.

As for turning the pagefile off, well I ran for nearly a month on just my 2 gigabytes of RAM with paging disabled just fine. It wasn't until I played the Witcher demo that my system complained I was running low on virtual memory. Crysis, World of Warcraft, UT3...they all ran just fine without it.