Page Filing with 2G of RAM?

[Think]

I understand the use of pagefiling as well as how to set my initial to 1.5 times of what I do have but that's rather rediculous when you have 2G of RAM.

The old thinking that page filing cannot be turned off because certain programs tend to allocate in virtual memory since there may not be enough ram.

Now most xtremesystems have 1G and in many others - such as myself 2G. So I don't see the point or am I missing something?

[Heretic]

I have 2gb of ram and a 2gb page file...I've never seen it fill more than halfway. If you're that worried about it, just monitor the page file usage when you do intensive tasks.

[KoolDrew]

The optimal pagefile size should be determined by your workload. Run your most intensive applications and then use perfmon to determine your actual PF usage. The initial size should be at least 4x the observed usage, while the max should be at least 2x that number.

Also, you should never disable the pagefile, all this will do is hurt you. First of all you have to realize the pagefile is NOT the only file involved with paging. All exe's and dl''s are also. So when you do disable the pagefile you have to keep all "private" data in RAM and only code and mapped files can be paged. Even if the "private" stuff has not been touched in hours. This will cause more paging of code. It also means that paging cannot be correctly balanced. It will also cripple the file cache and slow down code execution. Also not to mention some applications will fail without a pagefile.

[Think]

The optimal pagefile size should be determined by your workload. Run your most intensive applications and then use perfmon to determine your actual PF usage. The initial size should be at least 4x the observed usage, while the max should be at least 2x that number.

Also, you should never disable the pagefile, all this will do is hurt you. First of all you have to realize the pagefile is NOT the only file involved with paging. All exe's and dl''s are also. So when you do disable the pagefile you have to keep all "private" data in RAM and only code and mapped files can be paged. Even if the "private" stuff has not been touched in hours. This will cause more paging of code. It also means that paging cannot be correctly balanced. It will also cripple the file cache and slow down code execution. Also not to mention some applications will fail without a pagefile.

I've been running perf all day and will get a better indication by tonight. At the momenet i've allowed xp to setup it's own pagefiling and lets see what happens. I'll let you guys know.

[Dissolved]

I wouldnt disable it, but ive heard if you make it very small, it will force windows to use more memory (which should be better)

but i usualy leave it at defaults.

[KoolDrew]

I've been running perf all day and will get a better indication by tonight. At the momenet i've allowed xp to setup it's own pagefiling and lets see what happens. I'll let you guys know.

Letting Windows manage it is a good idea.

but ive heard if you make it very small, it will force windows to use more memory

This is false.

[Dngrsone]

Win does not work very well without the pagefile. Last time I tried shutting it off, machine locked up.

[Zeus...]

well if u have enough Ram why bother with the page file just use task manager to see how much mam u r using and if u dont use more mem than u have install disable the page file and enjoy - I do/did depends on which machine/graphics card and games/ application etc

then u u r going to only use mem intensive programs time to time switch the page file back on - its only a reboot away

I normally have a small partion of the hard drive set to one side for page file use only - keep all the fragmention in one place, not sure how much it helps but it cant hurt

[KoolDrew]

well if u have enough Ram why bother with the page file just use task manager to see how much mam u r using and if u dont use more mem than u have install disable the page file and enjoy - I do/did depends on which machine/graphics card and games/ application etc

This is very poor advice. Disabling the pagefile means that the system has to keep ALL "private" virtual memory in RAM; if there is more stuff in address space than there is RAM (and that is always the case), only code and mapped file pages can be paged, even if some of the "private" stuff hasn't been touched for hours and will never be touched again. This means there will be MORE paging of code, for a given workload and RAM size. It also means that paging cannot be correctly balanced between code, mapped files, the file cache, and private data. That's going to be a bad thing in the long run.

I normally have a small partion of the hard drive set to one side for page file use only - keep all the fragmention in one place, not sure how much it helps but it cant hurt

This actually does hurt. It hurts your performance because you are increasing your average seeking distance. Everytime you need to page to the pagefile the drive will have to seek over to that partition. If you hvae one drive the pagefile should be in the same partiton as your OS and applications. If you have more then one drive the pagefile should be on the least-used one and the most-used partition on that drive.

[Zeus...]

Thanks for that 'KoolDrew' will look into it some more -not that I am saying you r wrong

[KoolDrew]

Read the Memory Management chapter in Windows Internals (http://www.sysinternals.com/WindowsInternals.html). Then you will understand.

These may help too:

If I have a Windows XP machine that has lots of memory, can I improve performance by removing the pagefile? (http://www.windowsitpro.com/Article/ArticleID/42035/42035.html)
RAM, Virtual Memory, Pagefile and all that stuff (http://support.microsoft.com/default.aspx?scid=kb;en-us;555223)

Don't follow the first links advice on the "DisablePagingExecutive" tweak though. Also, don't just set the pagefile at 100MB and have a higher max. Either take the time to determine the optimal pagefile size or leave it System Managed.

The second link isn't completely correct either, but it is good enough for this case.

[mega]

Totals Physical Memroy (K)
Handles 10984 Total 2096628
Treads 517 Available 1559792
Processes 40 System Cache 809960

Commit Charge (K) Kernal Memory (K)
Total 407800 Total 110144
Limit 1940288 Paged 71432
Peak 548740 Nonpaged 38712


Disable page fill makes more data go on ~5gb/sec Ram speed vs Enabling page fill making it trash between (~60mb/sec)/(~5gb/sec) making a low performance on average.

For noobs they probably don't understand what they are doing. You see the peak vs total vs limit when you understand these things then you aren't a noob.Total is what it is using at the moment. Limit is how much you have in RAM. Peak is the Max it used so far.

Example when I load BF2 it shows 1200000~ or mmorpg server 1300000~ at peak. If you had a limit of 1000000 then you are going to experience out of memory syndromes. So the point is to have a limit that Peak can never reach and you will be fine with a data bandwidth highway that won't experience trashing effect of 60mb/sec on average use.

Even with page fill disable windows still uses some page fill mines uses 398mb. So there no prossible way for programs to not work I have zero problem from programs not working cause the pagefill option is disable but its not really100% disable by windows.

Also my peak is from running my normal windows xp with 40 processes + media player playing 704x396 video + Internet explorer

also people that saying 1 gig were enough didn't check their task manager if the peak is over what you have than your ram isn't enough and will result in out of memory syndrome. so simple formula is peak < limit = no problems.

On my system it might actually use more in BF2 it's peak is around 1200~1300mb + 512mb agp aperture memory = ~1700-1800mb so I would think 2gb is right for me.

also my agp card trashes between (7gb/sec 128mb) / (2.1gb/sec 512mb aperture mem) when 128mb is used up it shutters until aperture feed it more mem then its smooth again.

[KoolDrew]

Even with page fill disable windows still uses some page fill mines uses 398mb. So there no prossible way for programs to not work I have zero problem from programs not working cause the pagefill option is disable but its not really100% disable by windows.

No, it doesn't. You are still paging to disk, but not to the pagefile. I am assuming you are getting confused by the "PF usage" graph in task manager. Oddly enough, this is not your PF usage. It is the sum of the actual pagefile usage, plus the physical memory used to realize such virtual address space. You can think of this figure as the maximum potential pagefile usage: If somehow everything in RAM had to be dropped to make room for other stuff, this is how much pagefile space would be needed. Some of it will usually already be in the pagefile at any given moment.

If you want to know the current actual pagefile usage, get the current pagefile size from either explorer or the system control panel applet, then look at the "%usage" counter under the Pagefile object in the Performance applet, and multiply. However, since you have no pagefile it isn't being used.

Also, I don't think I have to explain why disabling the pagefile is a terrible idea. I already did twice in this one topic.

[Serra]

Lets not forget one primary reason the pagefile exists: in the event that something untoward happens, Windows will try to save all memory into the pagefile.. it can't throw it anywhere else. That's why your pagefile is always larger than your RAM. Other than that, there's no reason for it to be anywhere near the kind of size you see now. 1.5x 2GB would be ridiculous. Even 1GB of extra page file is unnecessary... but in a world of 400GB+ hard drives, what's 1GB anyway?

Serra

[uOpt]

Read the Memory Management chapter in Windows Internals (http://www.sysinternals.com/WindowsInternals.html). Then you will understand.

These may help too:

If I have a Windows XP machine that has lots of memory, can I improve performance by removing the pagefile? (http://www.windowsitpro.com/Article/ArticleID/42035/42035.html)
RAM, Virtual Memory, Pagefile and all that stuff (http://support.microsoft.com/default.aspx?scid=kb;en-us;555223)

Don't follow the first links advice on the "DisablePagingExecutive" tweak though. Also, don't just set the pagefile at 100MB and have a higher max. Either take the time to determine the optimal pagefile size or leave it System Managed.

The second link isn't completely correct either, but it is good enough for this case.

That first article is so off reality it's amazing. Jessus...

But yes if you get more RAM and keep your programs exactly the same you need less paging space.