Switch off the Windows Paging file?

[Platypus]

I've spent AGES Googling on this subject, so I wondered what people here think on the 'should I switch off windows paging file to improve performance' question.

Much of the 'wisdom' on the net seems to be quite old (you need a page file because you only have 256Mb of memory) or quite new (windows7 does paging well so leave it alone).

I accept that Windows7 (and Vista?) probably does paging much much better than XP, so I'll happily disregard any 'modern' advice that switching off paging makes no difference to system performance.

I'm thinking that for a common-or-garden Windows XP machine, used for Word, Outlook, Firefox (the usual sort of stuff) that 2GB of RAM will be enough to allow the page file to be switched off, thereby improving performance.

Rather than regurgitate all the old mis-information that's out there on t'internet, what does the panel think? What are your experiences of this?

Ta

[Moscow Mule]

I don't profess to know much about the ins and outs of this (the last time I had anything to do with it I was at uni), but I thought the paging file wasn't used unless the memory was fully utilised.

Regardless, I always let Windows deal with it itself.

[Platypus]

I don't profess to know much about the ins and outs of this (the last time I had anything to do with it I was at uni), but I thought the paging file wasn't used unless the memory was fully utilised.

Regardless, I always let Windows deal with it itself.

Well there's the rub: it seems (so I read) that Windows (XP) aggressively moves pages to the page file to free up RAM memory for 'more useful' things. For example, on your quiescent PC, run Task Manager and on the Performance tab, see how much 'PF Usage' there is. I think you'll be surprised (I was).

EDIT: ah... it seems that "PF Usage" in task Manager isn't what it says it is:

is not PF usage, but rather commit charge.
If you want a view of actual usage, try the WinXP-2K_Pagefile.zip script here

[Moscow Mule]

Well there's the rub: it seems (so I read) that Windows (XP) aggressively moves pages to the page file to free up RAM memory for 'more useful' things. For example, on your quiescent PC, run Task Manager and on the Performance tab, see how much 'PF Usage' there is. I think you'll be surprised (I was).

You learn something new every day.

[gingerjedi]

I have an XP machine with 2Gb of RAM and I'm off today, I'll try it this morning and let you know what happens.

[Platypus]

I have an XP machine with 2Gb of RAM and I'm off today, I'll try it this morning and let you know what happens.

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

[Clippy]

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).

[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).

[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.

[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.