Fast machine is slowed down by Virtual Memory.

Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
With 16GB RAM does Vista really need any virtual memory?

My quad core, 16GB RAM notebook would be faster without hard drive
access due to virtual memory.

Can I turm off virtual memory or set it to some very low value
(possibly 0)?

My preference is to use the 16GB RAM and should that be insufficient
then I decide which programs to close. I don't want Vista using 4GB, or
6GB RAM, etc., and continually writing/reading to HD which slows things
down and does not make full use of the physical RAM present.

Can Vista be instructed to first use all RAM and only when ALL RAM is
used then switch to virtual memory?


--
Laurence

 

Many programs are designed specifically to utilize virtual memory and will
malfunction in its absence. You won't know if you are affected until you try
it. And, 6 months down the road, when you install something like PhotoShop
(which needs virtual memory), will you even remember that you have it
disabled.

--

Richard Urban
Microsoft MVP
Windows Desktop Experience


"Laurence" <guest@unknown-email.com> wrote in message
news:85b8ad0036a52e667029c1e7145e7f55@nntp-gateway.com...<!--coloro:blue--><span style="color:blue <!--/coloro-->
>
> Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> With 16GB RAM does Vista really need any virtual memory?
>
> My quad core, 16GB RAM notebook would be faster without hard drive
> access due to virtual memory.
>
> Can I turm off virtual memory or set it to some very low value
> (possibly 0)?
>
> My preference is to use the 16GB RAM and should that be insufficient
> then I decide which programs to close. I don't want Vista using 4GB, or
> 6GB RAM, etc., and continually writing/reading to HD which slows things
> down and does not make full use of the physical RAM present.
>
> Can Vista be instructed to first use all RAM and only when ALL RAM is
> used then switch to virtual memory?
>
>
> --
> Laurence <!--colorc--><!--/colorc-->

 

Richard Urban wrote:<!--coloro:blue--><span style="color:blue <!--/coloro-->
> Many programs are designed specifically to utilize virtual memory and
> will malfunction in its absence. You won't know if you are affected
> until you try it. And, 6 months down the road, when you install
> something like PhotoShop (which needs virtual memory), will you even
> remember that you have it disabled.
> <!--colorc--><!--/colorc-->

Virtual memory is this context is something else. Applications can
function just fine without a paging file as long as there is enough free
ram.

 

"dennis" <1@1.invalid> wrote in message
news:O27R8d28JHA.1340@TK2MSFTNGP05.phx.gbl...<!--coloro:blue--><span style="color:blue <!--/coloro-->
> Richard Urban wrote:<!--coloro:green--><span style="color:green <!--/coloro-->
>> Many programs are designed specifically to utilize virtual memory and
>> will malfunction in its absence. You won't know if you are affected until
>> you try it. And, 6 months down the road, when you install something like
>> PhotoShop (which needs virtual memory), will you even remember that you
>> have it disabled.
>><!--colorc--><!--/colorc-->
>
> Virtual memory is this context is something else. Applications can
> function just fine without a paging file as long as there is enough free
> ram.<!--colorc--><!--/colorc-->

Depends on the application. There are some that will NOT function properly
without a page file....

 

Gordon wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
> Depends on the application. There are some that will NOT function
> properly without a page file....<!--colorc--><!--/colorc-->

Name one. And don't say "photoshop" like everyone does, because it can
do it just fine.

 

dennis wrote:<!--coloro:blue--><span style="color:blue <!--/coloro-->
> Gordon wrote:
> <!--coloro:green--><span style="color:green <!--/coloro-->
>> Depends on the application. There are some that will NOT function
>> properly without a page file....<!--colorc--><!--/colorc-->
>
> Name one. And don't say "photoshop" like everyone does, because it can
> do it just fine.<!--colorc--><!--/colorc-->

I would also like to hear what API call that will fail, if there is just
enough free ram...

 

"Laurence" <guest@unknown-email.com> wrote in message
news:85b8ad0036a52e667029c1e7145e7f55@nntp-gateway.com...<!--coloro:blue--><span style="color:blue <!--/coloro-->
>
> Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> With 16GB RAM does Vista really need any virtual memory?
>
> My quad core, 16GB RAM notebook would be faster without hard drive
> access due to virtual memory.
>
> Can I turm off virtual memory or set it to some very low value
> (possibly 0)?
>
> My preference is to use the 16GB RAM and should that be insufficient
> then I decide which programs to close. I don't want Vista using 4GB, or
> 6GB RAM, etc., and continually writing/reading to HD which slows things
> down and does not make full use of the physical RAM present.
>
> Can Vista be instructed to first use all RAM and only when ALL RAM is
> used then switch to virtual memory?
>
>
> --
> Laurence<!--colorc--><!--/colorc-->


That is pretty much what happens already unless a process specifically needs
to write to a pagefile.. for that reason, it is best to keep a pagefile..

If you have lots of free disk space, leave it as system managed..

BTW, all operating systems employ page files..


--

Mike Hall - MVP Windows Experience

 

Richard Urban;1072123 Wrote: <!--coloro:blue--><span style="color:blue <!--/coloro-->
> Many programs are designed specifically to utilize virtual memory and
> will
> malfunction in its absence. You won't know if you are affected until
> you try
> it. And, 6 months down the road, when you install something like
> PhotoShop
> (which needs virtual memory), will you even remember that you have it
> disabled.
>
> --
>
> Richard Urban
> Microsoft MVP
> Windows Desktop Experience
>
>
> "Laurence" <guest@xxxxxx-email.com> wrote in message
> news:85b8ad0036a52e667029c1e7145e7f55@xxxxxx-gateway.com...> > > <!--coloro:green--><span style="color:green <!--/coloro--><!--coloro:darkred--><span style="color:darkred <!--/coloro-->
> > >
> > > Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> > > With 16GB RAM does Vista really need any virtual memory?
> > >
> > > My quad core, 16GB RAM notebook would be faster without hard drive
> > > access due to virtual memory.
> > >
> > > Can I turm off virtual memory or set it to some very low value
> > > (possibly 0)?
> > >
> > > My preference is to use the 16GB RAM and should that be insufficient
> > > then I decide which programs to close. I don't want Vista using 4GB,<!--colorc--><!--/colorc-->
> > or<!--coloro:darkred--><span style="color:darkred <!--/coloro-->
> > > 6GB RAM, etc., and continually writing/reading to HD which slows<!--colorc--><!--/colorc-->
> > things<!--coloro:darkred--><span style="color:darkred <!--/coloro-->
> > > down and does not make full use of the physical RAM present.
> > >
> > > Can Vista be instructed to first use all RAM and only when ALL RAM is
> > > used then switch to virtual memory?
> > >
> > >
> > > --
> > > Laurence > > <!--colorc--><!--/colorc--><!--colorc--><!--/colorc--><!--colorc--><!--/colorc-->

Thanks for your reply.
Okay, since it gets more complicated with applications using virtual
memory (even when there are GB's of unused physical memory!) then can
Vista be instructed to first use all RAM and only when ALL RAM is used
then switch to virtual memory when needed or when an application
requires it?


--
Laurence

 

"Mike Hall - MVP" <mikehall@mvps.org> wrote in message
news:us9WAw28JHA.200@TK2MSFTNGP05.phx.gbl...<!--coloro:blue--><span style="color:blue <!--/coloro-->
> "Laurence" <guest@unknown-email.com> wrote in message
> news:85b8ad0036a52e667029c1e7145e7f55@nntp-gateway.com...<!--coloro:green--><span style="color:green <!--/coloro-->
>>
>> Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
>> With 16GB RAM does Vista really need any virtual memory?
>>
>> My quad core, 16GB RAM notebook would be faster without hard drive
>> access due to virtual memory.
>>
>> Can I turm off virtual memory or set it to some very low value
>> (possibly 0)?
>>
>> My preference is to use the 16GB RAM and should that be insufficient
>> then I decide which programs to close. I don't want Vista using 4GB, or
>> 6GB RAM, etc., and continually writing/reading to HD which slows things
>> down and does not make full use of the physical RAM present.
>>
>> Can Vista be instructed to first use all RAM and only when ALL RAM is
>> used then switch to virtual memory?
>>
>>
>> --
>> Laurence<!--colorc--><!--/colorc-->
>
>
> That is pretty much what happens already unless a process specifically
> needs to write to a pagefile.. for that reason, it is best to keep a
> pagefile..
>
> If you have lots of free disk space, leave it as system managed..
>
> BTW, all operating systems employ page files..
><!--colorc--><!--/colorc-->
I used to work in Windows development, a long time ago. I imagine that
"all" testing has been done with a page file present. If Laurence turns it
off he will be letting all kinds of bugs out...

Earle

 

On Mon, 22 Jun 2009 20:31:38 +0200, dennis <1@1.invalid> wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
> Richard Urban wrote:<!--coloro:green--><span style="color:green <!--/coloro-->
> > Many programs are designed specifically to utilize virtual memory and
> > will malfunction in its absence. You won't know if you are affected
> > until you try it. And, 6 months down the road, when you install
> > something like PhotoShop (which needs virtual memory), will you even
> > remember that you have it disabled.
> > <!--colorc--><!--/colorc-->
>
> Virtual memory is this context is something else. Applications can
> function just fine without a paging file as long as there is enough free
> ram.<!--colorc--><!--/colorc-->


Two points here:

1. If you don't have a page file, you can't use all the RAM you have.
That's because Windows preallocates virtual memory in anticipation of
a possible need for it, even though that allocated virtual memory may
never be used. Without a page file, that allocation has to be made in
real memory, thus tying up that memory and preventing it from being
used for any purpose.

2. There is never a benefit in not having a page file. If it isn't
needed, it won't be used. Don't confuse allocated memory with used
memory.

--
Ken Blake, Microsoft MVP - Windows Desktop Experience
Please Reply to the Newsgroup

 

In the "Advanced System Settings", Advanced tab, "Performance", Settings,
Advanced, Virtual Memory "Change", you can set Virtual Memory settings. One
of the options is "No paging file". Therefore, running your system without a
paging file is perfectly valid and supported option. You are free to test it
an keep it if you like it. Contrary to other posters' comments, applications
do not and cannot directly manipulate paging file. They can only request and
release pages of virtual memory. If the application cannot allocate required
virtual memory, it will signal this condition with an error mesage, like
"Insufficient memory". I personally like to have a paging file of the same
size as the physical memory of my computer (4GB on a 64-bit Vista). I also
like to turn off options "Automatically manage paging file for all drives"
an "System managed size" because when leaky application would request more
memory when all the virtual memory was exhausted, the system would extend
the paging file. This condition existed in some previous version of
Photoshop (CS). When that condition occured, rather than allowing system to
extend the paging file, I would simply clear history in Photoshop, save and
close the work and start again.


"Laurence" <guest@unknown-email.com> wrote in message
news:85b8ad0036a52e667029c1e7145e7f55@nntp-gateway.com...<!--coloro:blue--><span style="color:blue <!--/coloro-->
>
> Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> With 16GB RAM does Vista really need any virtual memory?
>
> My quad core, 16GB RAM notebook would be faster without hard drive
> access due to virtual memory.
>
> Can I turm off virtual memory or set it to some very low value
> (possibly 0)?
>
> My preference is to use the 16GB RAM and should that be insufficient
> then I decide which programs to close. I don't want Vista using 4GB, or
> 6GB RAM, etc., and continually writing/reading to HD which slows things
> down and does not make full use of the physical RAM present.
>
> Can Vista be instructed to first use all RAM and only when ALL RAM is
> used then switch to virtual memory?
>
>
> --
> Laurence <!--colorc--><!--/colorc-->

 

Ken Blake, MVP wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
> 1. If you don't have a page file, you can't use all the RAM you have.
> That's because Windows preallocates virtual memory in anticipation of
> a possible need for it, even though that allocated virtual memory may
> never be used. Without a page file, that allocation has to be made in
> real memory, thus tying up that memory and preventing it from being
> used for any purpose.<!--colorc--><!--/colorc-->

The section in the kb that once had that obscure statement has been removed.
<!--coloro:blue--><span style="color:blue <!--/coloro-->
>
> 2. There is never a benefit in not having a page file. If it isn't
> needed, it won't be used. Don't confuse allocated memory with used
> memory.<!--colorc--><!--/colorc-->

Maybe not. But that was not the point here.

 

On Mon, 22 Jun 2009 21:18:24 +0200, "Dusko Savatovic"
<nospam.savatovic@gmail.com> wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
> In the "Advanced System Settings", Advanced tab, "Performance", Settings,
> Advanced, Virtual Memory "Change", you can set Virtual Memory settings. One
> of the options is "No paging file". Therefore, running your system without a
> paging file is perfectly valid and supported option. <!--colorc--><!--/colorc-->


Yes, you *can* do that. However it's almost invariably a very bad
thing to do. As I said in an earlier message in this thread,

"1. If you don't have a page file, you can't use all the RAM you have.
That's because Windows preallocates virtual memory in anticipation of
a possible need for it, even though that allocated virtual memory may
never be used. Without a page file, that allocation has to be made in
real memory, thus tying up that memory and preventing it from being
used for any purpose.

2. There is never a benefit in not having a page file. If it isn't
needed, it won't be used. Don't confuse allocated memory with used
memory."


<!--coloro:blue--><span style="color:blue <!--/coloro-->
> You are free to test it
> an keep it if you like it. Contrary to other posters' comments, applications
> do not and cannot directly manipulate paging file. They can only request and
> release pages of virtual memory. If the application cannot allocate required
> virtual memory, it will signal this condition with an error mesage, like
> "Insufficient memory". I personally like to have a paging file of the same
> size as the physical memory of my computer (4GB on a 64-bit Vista). I also
> like to turn off options "Automatically manage paging file for all drives"
> an "System managed size" because when leaky application would request more
> memory when all the virtual memory was exhausted, the system would extend
> the paging file. This condition existed in some previous version of
> Photoshop (CS). When that condition occured, rather than allowing system to
> extend the paging file, I would simply clear history in Photoshop, save and
> close the work and start again.
>
>
> "Laurence" <guest@unknown-email.com> wrote in message
> news:85b8ad0036a52e667029c1e7145e7f55@nntp-gateway.com...<!--coloro:green--><span style="color:green <!--/coloro-->
> >
> > Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> > With 16GB RAM does Vista really need any virtual memory?
> >
> > My quad core, 16GB RAM notebook would be faster without hard drive
> > access due to virtual memory.
> >
> > Can I turm off virtual memory or set it to some very low value
> > (possibly 0)?
> >
> > My preference is to use the 16GB RAM and should that be insufficient
> > then I decide which programs to close. I don't want Vista using 4GB, or
> > 6GB RAM, etc., and continually writing/reading to HD which slows things
> > down and does not make full use of the physical RAM present.
> >
> > Can Vista be instructed to first use all RAM and only when ALL RAM is
> > used then switch to virtual memory?
> >
> >
> > --
> > Laurence <!--colorc--><!--/colorc--><!--colorc--><!--/colorc-->

--
Ken Blake, Microsoft MVP - Windows Desktop Experience
Please Reply to the Newsgroup

 

I don't know why you say "Yes, you *can* do that", emphasizing *can* when
this is perfectly valid option. In fact I did test this option in the past
with 32-bit WinXp and Photoshop CS on a 1GB system. And I did like this
option at the time because Photoshop CS was a leaky application and I would
quickly see when that condition occured. The "Brigde" application of Adobe
CS was particularly leaky. Still, it did not give me major headaches. The
memory leak in Photoshop CS would typically start after long period of work
with many layers, many 'copy' and 'pastes' and large resolution. The quick
remedy would be 'clear history', 'save', 'close', 'open'.

I would appreciate if you could post some links to the technical articles
that address this issue, specially for 64-bit systems.

Thanks and regards
DuskoS


"Ken Blake, MVP" <kblake@this.is.an.invalid.domain> wrote in message
news:9nmv35lsbo2ijb43hvbl6ge6adcodns02c@4ax.com...<!--coloro:blue--><span style="color:blue <!--/coloro-->
> On Mon, 22 Jun 2009 21:18:24 +0200, "Dusko Savatovic"
> <nospam.savatovic@gmail.com> wrote:
><!--coloro:green--><span style="color:green <!--/coloro-->
>> In the "Advanced System Settings", Advanced tab, "Performance", Settings,
>> Advanced, Virtual Memory "Change", you can set Virtual Memory settings.
>> One
>> of the options is "No paging file". Therefore, running your system
>> without a
>> paging file is perfectly valid and supported option.<!--colorc--><!--/colorc-->
>
>
> Yes, you *can* do that. However it's almost invariably a very bad
> thing to do. As I said in an earlier message in this thread,
>
> "1. If you don't have a page file, you can't use all the RAM you have.
> That's because Windows preallocates virtual memory in anticipation of
> a possible need for it, even though that allocated virtual memory may
> never be used. Without a page file, that allocation has to be made in
> real memory, thus tying up that memory and preventing it from being
> used for any purpose.
>
> 2. There is never a benefit in not having a page file. If it isn't
> needed, it won't be used. Don't confuse allocated memory with used
> memory."
>
>
><!--coloro:green--><span style="color:green <!--/coloro-->
>> You are free to test it
>> an keep it if you like it. Contrary to other posters' comments,
>> applications
>> do not and cannot directly manipulate paging file. They can only request
>> and
>> release pages of virtual memory. If the application cannot allocate
>> required
>> virtual memory, it will signal this condition with an error mesage, like
>> "Insufficient memory". I personally like to have a paging file of the
>> same
>> size as the physical memory of my computer (4GB on a 64-bit Vista). I
>> also
>> like to turn off options "Automatically manage paging file for all
>> drives"
>> an "System managed size" because when leaky application would request
>> more
>> memory when all the virtual memory was exhausted, the system would extend
>> the paging file. This condition existed in some previous version of
>> Photoshop (CS). When that condition occured, rather than allowing system
>> to
>> extend the paging file, I would simply clear history in Photoshop, save
>> and
>> close the work and start again.
>>
>>
>> "Laurence" <guest@unknown-email.com> wrote in message
>> news:85b8ad0036a52e667029c1e7145e7f55@nntp-gateway.com...<!--coloro:darkred--><span style="color:darkred <!--/coloro-->
>> >
>> > Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
>> > With 16GB RAM does Vista really need any virtual memory?
>> >
>> > My quad core, 16GB RAM notebook would be faster without hard drive
>> > access due to virtual memory.
>> >
>> > Can I turm off virtual memory or set it to some very low value
>> > (possibly 0)?
>> >
>> > My preference is to use the 16GB RAM and should that be insufficient
>> > then I decide which programs to close. I don't want Vista using 4GB, or
>> > 6GB RAM, etc., and continually writing/reading to HD which slows things
>> > down and does not make full use of the physical RAM present.
>> >
>> > Can Vista be instructed to first use all RAM and only when ALL RAM is
>> > used then switch to virtual memory?
>> >
>> >
>> > --
>> > Laurence<!--colorc--><!--/colorc--><!--colorc--><!--/colorc-->
>
> --
> Ken Blake, Microsoft MVP - Windows Desktop Experience
> Please Reply to the Newsgroup <!--colorc--><!--/colorc-->

 

Laurence <guest@unknown-email.com> wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
>Okay, since it gets more complicated with applications using virtual
>memory (even when there are GB's of unused physical memory!) then can
>Vista be instructed to first use all RAM and only when ALL RAM is used
>then switch to virtual memory when needed or when an application
>requires it?<!--colorc--><!--/colorc-->

Dream on. The few milliseconds you might save IF that were possible
aren't worth the effort OR any more space here in discussion.

 

Bill Daggett;1072289 Wrote: <!--coloro:blue--><span style="color:blue <!--/coloro-->
> Laurence <guest@xxxxxx-email.com> wrote:<!--coloro:green--><span style="color:green <!--/coloro--><!--coloro:darkred--><span style="color:darkred <!--/coloro-->
> > > >
> > >Okay, since it gets more complicated with applications using virtual
> > >memory (even when there are GB's of unused physical memory!) then can
> > >Vista be instructed to first use all RAM and only when ALL RAM is used
> > >then switch to virtual memory when needed or when an application
> > >requires it? > > <!--colorc--><!--/colorc--><!--colorc--><!--/colorc-->
>
> Dream on. The few milliseconds you might save IF that were possible
> aren't worth the effort OR any more space here in discussion.<!--colorc--><!--/colorc-->

Read/write speed to/from RAM >>> Read/write speed to/from mechanical
hard drive.

Therefore using all RAM is preferable before using virtual memory,
especially when one has systems with 16-64GB RAM.

However the following statement, if I read it correctly, is that Vista
64-bit will only use virtual memory (i.e., write/read to HD) when no
more RAM is available (?):

"2. There is never a benefit in not having a page file. If it isn't
needed, it won't be used. Don't confuse allocated memory with used
memory."


--
Laurence

 

dennis wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
> I would also like to hear what API call that will fail, if there is just
> enough free ram...<!--colorc--><!--/colorc-->

I'm just being pedantic but I think CreateFileMapping() will fail,
if there is no backing store ... especially if the SEC_LARGE_PAGES flag
is used.

Of course, how many apps actually *use* this particular call is another
matter ...

Cheers
Andrew
--
amclar at optusnet dot com dot au

 

Laurence wrote:<!--coloro:blue--><span style="color:blue <!--/coloro-->
> Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> With 16GB RAM does Vista really need any virtual memory?
> Can Vista be instructed to first use all RAM and only when ALL RAM is
> used then switch to virtual memory?<!--colorc--><!--/colorc-->

Hi Laurence

As you can see from he replies, this question usually generates a lot of
heat, and misinformation.

You can turn the paging file off under System, Properties, Advanced,
Performance, Paging File. Select the third radio button, "No paging
file", below "Custom" and "system-managed".

However, it is very unlikely disabling the paging file will do anything
to improve performance; it may even cause some drop in performance,
depending on your particular applications and scenario.

Windows NT (including 2000, XP, 2003, and Vista) is designed from the
ground up as a virtual memory operating system. You can't turn virtual
memory "off", because the Memory Manager will *always* be performing
virtual-to-physical page address translation. All that you achieve by
having no paging file is to remove the disk-based backing store for
virtual pages which don't fit in physical memory.

Since day one, NT's Memory Manager has used much more sophisticated
paging disciplines than a simple, naive "write stuff to disk". For
example, NT uses a file mapping and copy-on-write schemes, to map pages
of disk files to virtual memory addresses. This eliminates the need to
read those pages into physical memory before they are used. If the pages
are never used, they're never even read off the disk in the first place;
let alone being paged out to the paging file later on. It sounds kind of
counter-intuitive; but that's why the smartest people at Microsoft have
been working on the memory management to optimise and streamline its
performance since 1993 - guys like Landy Wang and Bruce Worthington.
They understand very well that Disk IO is hugely expensive is terms of
time, so the Memory Manager avoids doing any IO to disk which does not
have a clear benefit for overall performance.

As usual, the canonical reference to get a better understanding of
Windows Memory management is Mark Russinovich's book "Microsoft Windows
Internals, 4th edition". There is a long and detailed chapter there
which explains all this in more detail.

With 16GB of RAM, it is unlikely that your system will be doing much
heavy paging due to memory pressure; any paging which occurs will be to
support memory-mapped files etc. A "small" paging file of, say 2GB will
probably provide enough room for effective virtual memory operations,
without chewing up too much disk space.

As in all cases, more precise calibration of performance requirements
would Performance Monitor and/or profiling, so you can understand just
what the system is actually doing and where the bottlenecks are.

Hope this helps,

Andrew
--
amclar at optusnet dot com dot au

 

Andrew McLaren;1072377 Wrote: <!--coloro:blue--><span style="color:blue <!--/coloro-->
> Laurence wrote:> > > <!--coloro:green--><span style="color:green <!--/coloro--><!--coloro:darkred--><span style="color:darkred <!--/coloro-->
> > > Running Vista Ultimate 64-bit on M6400 notebook with 16GB RAM.
> > > With 16GB RAM does Vista really need any virtual memory?
> > > Can Vista be instructed to first use all RAM and only when ALL RAM is
> > > used then switch to virtual memory? > > <!--colorc--><!--/colorc--><!--colorc--><!--/colorc-->
>
> Hi Laurence
>
> As you can see from he replies, this question usually generates a lot
> of
> heat, and misinformation.
>
> You can turn the paging file off under System, Properties, Advanced,
> Performance, Paging File. Select the third radio button, "No paging
> file", below "Custom" and "system-managed".
>
> However, it is very unlikely disabling the paging file will do
> anything
> to improve performance; it may even cause some drop in performance,
> depending on your particular applications and scenario.
>
> Windows NT (including 2000, XP, 2003, and Vista) is designed from the
> ground up as a virtual memory operating system. You can't turn
> virtual
> memory "off", because the Memory Manager will *always* be performing
> virtual-to-physical page address translation. All that you achieve by
> having no paging file is to remove the disk-based backing store for
> virtual pages which don't fit in physical memory.
>
> Since day one, NT's Memory Manager has used much more sophisticated
> paging disciplines than a simple, naive "write stuff to disk". For
> example, NT uses a file mapping and copy-on-write schemes, to map
> pages
> of disk files to virtual memory addresses. This eliminates the need
> to
> read those pages into physical memory before they are used. If the
> pages
> are never used, they're never even read off the disk in the first
> place;
> let alone being paged out to the paging file later on. It sounds kind
> of
> counter-intuitive; but that's why the smartest people at Microsoft
> have
> been working on the memory management to optimise and streamline its
> performance since 1993 - guys like Landy Wang and Bruce Worthington.
> They understand very well that Disk IO is hugely expensive is terms
> of
> time, so the Memory Manager avoids doing any IO to disk which does
> not
> have a clear benefit for overall performance.
>
> As usual, the canonical reference to get a better understanding of
> Windows Memory management is Mark Russinovich's book "Microsoft
> Windows
> Internals, 4th edition". There is a long and detailed chapter there
> which explains all this in more detail.
>
> With 16GB of RAM, it is unlikely that your system will be doing much
> heavy paging due to memory pressure; any paging which occurs will be
> to
> support memory-mapped files etc. A "small" paging file of, say 2GB
> will
> probably provide enough room for effective virtual memory operations,
> without chewing up too much disk space.
>
> As in all cases, more precise calibration of performance requirements
> would Performance Monitor and/or profiling, so you can understand
> just
> what the system is actually doing and where the bottlenecks are.
>
> Hope this helps,
>
> Andrew
> --
> amclar at optusnet dot com dot au<!--colorc--><!--/colorc-->

Appreciated.


--
Laurence

 

Andrew McLaren wrote:
<!--coloro:blue--><span style="color:blue <!--/coloro-->
> I'm just being pedantic but I think CreateFileMapping() will fail,
> if there is no backing store ... especially if the SEC_LARGE_PAGES flag
> is used.
>
> Of course, how many apps actually *use* this particular call is another
> matter ...<!--colorc--><!--/colorc-->


It doesn't.