Reply to: Switch off the Windows Paging file?

[Platypus]

I'd love to tell you my well argued view on this one, however it would be revealing priviledged information so I won't. In 30 years time though - assuming any of you will still be alive

If you have nothing to add, please add nothing.

For the benefit of anyone else who might be interested, I've switched my paging file OFF again because the machine was running so slowly (when manipulating a large image file). And I noticed that Windows had swapped out 280Mb of memory while there was more than 800Mb of 'unused' actual core memory.

[AtW]

I'd love to tell you my well argued view on this one, however it would be revealing priviledged information so I won't. In 30 years time though - assuming any of you will still be alive

[Platypus]

Update: After 3 weeks running with no Paging file on Windows, I got my first "out of memory" error yesterday (using PaintShop Pro to modify a huge image file). I killed off a few other large processes and got done what I needed to.

But I've now switched paging space back on.

In the interim, my XP PC has been pretty nippy. I wonder if it'll slow back down now paging is back in play.

[Sysman]

Yes that worked brilliantly in 1987 grandad.

l

1995 with Windows 95
1998 with Windows 98
1999 with Windows SE
2000 with WIndows ME

All the above were still Windows on top of DOS, no matter how they tried to disguise it.

[Churchill]

Yes that worked brilliantly in 1987 grandad.

Also, try adding a 5 and 1/4 inch disk subsystem and an EGA graphics card.

Jeez.

Get a sense of humour. While you're there pick one up for Sasguru.

[DimPrawn]

Make sure you've got himem.sys and ramdrive.sys in your config.sys file and then configure windows so that it can put your swap file into a ramdrive!

Simples!

Yes that worked brilliantly in 1987 grandad.

Also, try adding a 5 and 1/4 inch disk subsystem and an EGA graphics card.

Jeez.

[Churchill]

Make sure you've got himem.sys and ramdrive.sys in your config.sys file and then configure windows so that it can put your swap file into a ramdrive!

Simples!

[Sysman]

You can actually find a very detailed explanation on how a fairly dated nt kernel still found in win7 relies on existence of swap.

Do you have any pointers to sources?

I probably wouldn't run anything critical on Windows boxes, but if a client has such a requirement, then I'd much rather get a call that the website is slow (because of swapping) in the morning, rather than the website has been offline since 4am...

Ditto. Given large dollops of RAM, I would rather dedicate it to specific applications. The benefits could probably be measured much more easily. Putting high traffic web files onto a RAM disk is one idea.

Other advantages to a good swap system (which XP isn't) is on average swapping an unused block of ram in exchange for a disk cache/prefetch usually result in a much smoother performance overall (app startup and responsivness).

By contrast, various releases of OS X have brought substantial and tangible improvements in the areas of swap system and memory management. This really did extend the usable life of my ancient iBook far beyond my expectations.

[Sysman]

I'm guessing here but I would leave it as it is and let Windows decide if it wants to write to the pagefile or not.

If it wants to and you have it turned off, it's gonna be shuffling stuff around in RAM so may well cause you a similar bottleneck to if you had the pagefile turned on and it was shuffling stuff between RAM and the pagefile.

Six of one and all that.

(To improve performance, you could defrag your pagefile using PageDefrag).

I haven't tried this with anything later than NT4, but if you created a pagefile on an already fragmented disk, it would act as a garbage collector, picking up all the small bits of free space that lying around. I've a vague memory that you could end up with too many mapping pointers and end up with an unbootable system.

When NT4 came out much was made of Dave Cutler's input with his knowledge of VMS, but VMS had solved this problem back in 1982 with "best try contiguous" file attributes. I concluded that Cutler's experience with VMS hadn't included some of the improvements that made it so famously reliable (i.e he'd left the project before a lot of these goodies were put in).

A lot of enhancements to swapping algorithms, memory usage and process scheduling were added to VMS in the following years, and are probably absent from the Windows NT family.

[vetran]

need paging file for reasons above.

If its paging it needs more memory or attention.

Fix the problem not remove the airbag.

[Durbs]

I've seen several benchmark tests where a decent amount of memory is installed and paging disabled altogether and the result was always it would perform the same or worse with no page file. NEVER better.

[VectraMan]

My Dad installed some kind of "security" program on his 1GB Vista machine, and that switched off the paging file. Everything went to hell.

Of course Vista and 1GB was never a good idea.

Windows 7 does seem a lot better at managing the memory, and doesn't err on the side of keeping memory free like XP does. But then XP came out in the era of 128MB being a lot.

[doodab]

Switching it off disables crash memory dumps.

As to whether it makes any difference to performance, try measuring it before and after. The only difference I have found is that without it things just stop working instead of descending into thrashing.

[gingerjedi]

Thanks! I've switched off my paging file too (this morning). I also have 2GB RAM.

I'm asking the question before I unleash this 'fix' on a customer PC

Mine is showing as switched off and I've rebooted, task manager still shows 50Mb as paged?? Must be what xchaotic mentioned.

[xchaotic]

You can actually find a very detailed explanation on how a fairly dated nt kernel still found in win7 relies on existence of swap.
Even on systems with 24GB RAM I recommend keeping it on for system stability.

Basically if the swap subsystem works correctly you shouldn't see much swap usage, but if a bad program leaks memory and fills all available physical RAM there are two scenarios:
a) with swap disabled there will be no memory left and you will see a BSOD and need to reboot a machine
b) with swap it will continue to swap out to disk, but at least you can log in and kill/restart the offending process.

I probably wouldn't run anything critical on Windows boxes, but if a client has such a requirement, then I'd much rather get a call that the website is slow (because of swapping) in the morning, rather than the website has been offline since 4am...

Other advantages to a good swap system (which XP isn't) is on average swapping an unused block of ram in exchange for a disk cache/prefetch usually result in a much smoother performance overall (app startup and responsivness).