P
Paul B T Hodges
Hey Everyone,
I thought I'd have a play with memory today and try and get a better
understanding of how windows xp reports its memory usage in task manager and
system information, which has always seemed a bit of a grey area.
I thought I'd make things easier to understand if I started with a system
that didn't have a pagefile. This system has 512MB, so I set no page file
and rebooted.
I ran systeminfo from a command prompt and this is what it reported.
Total Physical Memory: 511 MB
Available Physical Memory: 292 MB
Virtual Memory: Max Size: 994 MB
Virtual Memory: Available: 618 MB
Virtual Memory: In Use: 376 MB
Why 511 and not 512 I'm not sure, unless this goes back to the days of dos
up to 640K and then expanded memory up to 1MB
Where does it get these virtual memory numbers from when there isn't any
pagefile, I've checked and it hasn't created a temporary page file.
Task manager performance screen reports max commit = 494326K
which if you add the kernel 30688K isn't that far away from 512mb, that
seems reasonable.
Task manager always appears to report the commit limit as roughly the sum
of the physical memory + Pagefile - Kernel(I've tried with several pagefile
sizes), I'll live with that. However the PF usage reported by task manager
would actually appear to be that total commit figure , not the amount of
memory removed to disk, otherwise it would be zero, with no page file
selected !
There seems to be conflicting definitions throughout windows xp of whether
virtual memory is actually just the pagefile, or, as in other operating
systems, is the sum of physical memory + the pagefile.
Same info comes out through msinfo32 aswell, only it throws in yet another
anomally of
Page File Space 483MB.
What page file ? This figure is at least consistent with the ones above if
in this case you use
total virtual = Total phys ram+pagefile = 511+483=994.
Anyone want to shed any light on these VM numbers ?
What does the systeminfo command report on your system vs your pagefile size
and physical memory size.
Perplexed :-(
Paul
I thought I'd have a play with memory today and try and get a better
understanding of how windows xp reports its memory usage in task manager and
system information, which has always seemed a bit of a grey area.
I thought I'd make things easier to understand if I started with a system
that didn't have a pagefile. This system has 512MB, so I set no page file
and rebooted.
I ran systeminfo from a command prompt and this is what it reported.
Total Physical Memory: 511 MB
Available Physical Memory: 292 MB
Virtual Memory: Max Size: 994 MB
Virtual Memory: Available: 618 MB
Virtual Memory: In Use: 376 MB
Why 511 and not 512 I'm not sure, unless this goes back to the days of dos
up to 640K and then expanded memory up to 1MB
Where does it get these virtual memory numbers from when there isn't any
pagefile, I've checked and it hasn't created a temporary page file.
Task manager performance screen reports max commit = 494326K
which if you add the kernel 30688K isn't that far away from 512mb, that
seems reasonable.
Task manager always appears to report the commit limit as roughly the sum
of the physical memory + Pagefile - Kernel(I've tried with several pagefile
sizes), I'll live with that. However the PF usage reported by task manager
would actually appear to be that total commit figure , not the amount of
memory removed to disk, otherwise it would be zero, with no page file
selected !
There seems to be conflicting definitions throughout windows xp of whether
virtual memory is actually just the pagefile, or, as in other operating
systems, is the sum of physical memory + the pagefile.
Same info comes out through msinfo32 aswell, only it throws in yet another
anomally of
Page File Space 483MB.
What page file ? This figure is at least consistent with the ones above if
in this case you use
total virtual = Total phys ram+pagefile = 511+483=994.
Anyone want to shed any light on these VM numbers ?
What does the systeminfo command report on your system vs your pagefile size
and physical memory size.
Perplexed :-(
Paul