Pagefile usage

[Eldonko]

Hey guys, I am curious how a pagefile actually works.

I have noticed that EQ2 is super laggy latey and it seems like its RAM related. There is no way I should be getting that kind of lag in a game with this rig and it seems like it just showed up.

I always thought a pagefile was used only when RAM was 100% used, is that not correct? I pulled up task manager while in the game and saw PF was at over a gig of usage. Is that what is causing lag? Also when idle I am using >311mb of PF. Is this normal or is something screwed up? See what I mean, RAM use 21% PF 300mb+



Can someone provide an explanation as to how swap/PF works please?

Cheers

[k0NG0]

The page file is always used in a demand paging design. The memory manager frequently writes unused memory pages to the page file. For the simple reason that if a page hasn't been used for a while, there's no need to bother memory with it. If a program then tries to read data that isn't in memory, the page is swapped back from the page file to the memory, and execution continues.

The most important use of a page file is for virtual memory. Even though you may only have 512MB of memory in XP, each process has 4GB of virtual memory. This is solved by using the page file and continuously writing memory pages that aren't used to the page file. You still only have 512MB of physical memory, but using the page file and demand paging, you can accomplish a virtual memory of 4GB.

(Problems may arise from this system also. Namely thrashing. That is when the system spends more time swapping memory pages to and from the page file than it does executing code. This is usually an indication that more physical memory is needed. I would say it's quite uncommon today in PCs.)

Some disable the page file when they have a couple of gigs of memory, but that is really disabling a feature that is key to operating systems. If memory should run you, at best you'll get a warning and you'll be allowed to close processes that hog memory, at worst the computer will BSOD and all work is lost.

[pointreyes]

I wonder if PAE is part of the problem as well?

The primary driver compatibility concern is running Physical Address Extension (PAE) mode on 32-bit systems. PAE mode enables processors to address greater than 4 gigabytes (GB) of memory. The primary difference between PAE memory paging and non-PAE memory paging schemes is the extra level of paging that is required in PAE mode (3 levels instead of 2).
.....
The largest driver PAE compatibility issue involves direct memory access (DMA) transfers and map register allocation. Many devices that support DMA, usually 32-bit adapters, are not capable of performing 64-bit physical addressing. When run in 32-bit mode, the device can address all physical address space. In PAE mode, it is possible that data would be present at a physical address greater than 4 GB. To allow devices with these constraints to function in this scenario, The Windows 2000 Server family and later provide double-buffering for the DMA transaction by providing a 32-bit address that is indicated by a map register. The device can perform the DMA transaction to the 32-bit address and the kernel copies the memory to the 64-bit address that is provided to the driver.

PAE which is enabled on your system was done so because you have a DEP chip.
http://www.microsoft.com/technet/pro.../sp2mempr.mspx

[TweakHound]

Perris, a member here and at OSNN wrote a good article on it. It is posted here:
http://www.tweakhound.com/xp/virtualmemory.htm

[sorrow]

You could always try disabling page file (: its like going into the wild without a machette hehe last time i did it, my sound would stop working lol

I might have to try that again though.

[Eldonko]

Thanks for the info guys. Does 1gb of pagefile usage while in a game sound normal? Seemed pretty high to be. I am trying to figure out this damn lag problem, its driving me nuts

I don’t think I will disable pagefile, but maybe reducing the size to 1024mb will help?

[sorrow]

When i played eq2 i don't think i hit 1 gig of pagefile usage, now close to 1gig of mem being used was normal though.

[MrMike]

The lag you are seeing could also be the video card swapping textures out of memory and not have anything to do with system memory. When playing world of warcraft if I go into an area I haven't been to recently I get the chop chop chop of the screen as it swaps textures out and loads new ones and loads in everything in the area. When you are playing EQ2 how much memory is the game taking up? I'm willing to bet that while in the game none of the EQ2 stuff is paged, but when you switch out to the desktop it pages it out to the HD since its such a large chunk. Then when you alt-tab back into the game it pages it again dumping it back into memory.

Windows XP's virtual memory system sucks. It should only page out to the hd when it is running low on physical memory, not when you switch applications.

[Eldonko]

Originally Posted by MrMike

The lag you are seeing could also be the video card swapping textures out of memory and not have anything to do with system memory. When playing world of warcraft if I go into an area I haven't been to recently I get the chop chop chop of the screen as it swaps textures out and loads new ones and loads in everything in the area. When you are playing EQ2 how much memory is the game taking up? I'm willing to bet that while in the game none of the EQ2 stuff is paged, but when you switch out to the desktop it pages it out to the HD since its such a large chunk. Then when you alt-tab back into the game it pages it again dumping it back into memory.

Windows XP's virtual memory system sucks. It should only page out to the hd when it is running low on physical memory, not when you switch applications.

I'm not sure how much memory is actually being used, but I can check tonight, whats the best way, everest? I assume its near a gig though. The lag is there with EQ in windowed or full screen mode so I am not sure if it is paging the stuff more in windowed mode or not. I suppose I could throw in another gig and see what happens.

I was guessing it was memory related because the game is acting like when I only had 512 in a while back, just choppy and gets worse when there are battles and stuff.

I have my 6800GT water cooled so it peaks at 44C and can't be overheating, and I have it Oced to 425/1100 for the last few months and have had no troubles at all. ..

[MrSeanKon]

Eldonko I always set fixed = constant page file size.
This helps for better and faster defrag.
In addition if you have a faster hard disk or a small partition --> thus fast access hard disk time --> place swap file there.
I have 1X512MB and page file size is 128MB only!
LOL I run my system on limits!

MrMike you are right.
Of course Windows virtual memory system sucks!
If I do not manage swap file it will be 1.5*times bigger than physical memory (Microsoft recommendation) --> 768MB...

My previous system
First of all here is a screen capture



and my CPU ZZZed --> CPU usage was 10% only....
Total processes were 38 but focus in Commit Charge (K) group item....
Total item shows the current memory usage (also MemTurbo does it) but Limit item is the maximum available RAM (plus swap file if exists)...
Moreover Peak item shows the maximum allocated RAM during Windows session LOL as you see my system used 481360 KB and the limit was 490208!
WOW very near to limits!!!!!
And system did not crash!

This photo shows the total processes see on the bottom left 3 antivirus were running (AntivirXP, Kasperksy and AVG) and 286 is the free RAM (MemTurbo index)...

[MrSeanKon]

Here was the settings for swap file (or pagefile):



Fixed size to 128 MB but I put it in the second hard disk (the IDE Western Digital).
My IDE has two partitions and pagefile is in the first partition cos the first sectors (outer) of each hard disk are faster.
The SATA Seagate is the main hard disk (Windows XP installed in SEAGATE_1 partition).

Finally this photo shows double video encoding (two DrDivX instances run) and I was programming C# (the mouse pointer shows Microsoft Visual Studio)...



Roughly 200 MB of total RAM were free (621276 vs 421528 KB)...
Thus why I must follow Microsoft recommendations?
LOL...

[MrSeanKon]

--> Let's play with System Reporter <--
This program is not in OcBible v1.47 but I share a beta version.
I will include it in OcBible v1.48 anyway click here to grab it and read there the instructions.

LOL Windows Task Manager shows wrong value for swap file!



System Reporter show the same value

[MrSeanKon]

The system has 2*512 MB total RAM so I opened many applications.
Guidemania C# code has huge forms who are hungry for RAM....
See here LOL system almost crashed!



Focus to values:

[MrSeanKon]

System Reporter can warn you blinking the monitor if something is out of limits.
Just click on the menus you want:





For pagefile:

[MrSeanKon]

Finally you can BAN LOL the monitoring values you do not want to save %CPU usage:



Enjoy with this new tool!