Understanding Page File

[asus killer]

So i get the basics and i watched Linus video, still i got a few questions:

 

Why does windows recommend a page file size 1915MB and then uses 4864MB?

 

Another thing i never seen my desktop even near using the 8GB, it never goes above 5'ish GB of RAM, even watching youtube videos and playing a game at the same time. (VRAM was very close to max but still not there). It's always using a lot of page file.

Shouldn't windows use a little more RAM and less page file?

 

I don't mean to say the PC is not performing, i see no issues, just trying to get an idea how this works. 

[SupaKomputa]

All active / foreground data need to be accessed straight from the memory.

Pagefile is used when windows detected that the system memory is low, so its moving the inactive / background / low priority data to the pagefile.

Moving data to the pagefile creates more headroom if a new request needed to access the memory.

If the background data is moved to the foreground, windows will move it from pagefile to the system memory.

Moving data back and forth to from the hdd disk (pagefile) to the memory is very slow.

This will bottleneck the experience. Having a faster drive will help.

 

That's why you never see the ram fill up to max. And that's when you know you need more memory.

[asus killer]

3 minutes ago, SupaKomputa said:

That's why you never see the ram fill up to max. And that's when you know you need more memory.

i understand all you said, but you lost me at the conclusion. If the RAM never fills up to max how do i know if i need more RAM? when it passes a % of pagefile use relative to RAM? 

[SupaKomputa]

 

funny how windows 10 doesn't display pagefile use in task manager, but you can use meminfo for this.

 

I use windows 7 desktop gadget with system monitor II extension for this.

as you can see on a 16gb i rarely used any pagefile.

[unknownmiscreant]

Its down to windows placing standby memory allocated to programs which they are not currently using in the pagefile. I wrote an explanation for it a while ago, its one of the replies in this thread:

 

 

[SupaKomputa]

I agree, unless you're very tight on hdd space, i would leave the pagefile to auto, even on 16gb memory.

[unknownmiscreant]

Just now, SupaKomputa said:

I agree, unless you're very tight on hdd space, i would leave the pagefile to auto, even on 16gb memory.

No, set it with a min size under 100mb and max of 4-8gb or so. That means it is only used if necessary. So is the best of both worlds. I have done that for a few years with no issues.

[GoodBytes]

4 hours ago, asus killer said:

i understand all you said, but you lost me at the conclusion. If the RAM never fills up to max how do i know if i need more RAM? when it passes a % of pagefile use relative to RAM? 

Keep in mind that:

• RAM is NEVER fragmented
• data on RAM is NEVER moved inside while the program is running.

So what happens, when you open and close and open many different programs, where you end up that you have, say 1GB of RAM free in total, you open a program that needs 300MB (say), but this 1GB of RAM, is 10x 100MB of free space blocks spread across the RAM between programs. How can it load your program? Remember it can't split the program blocks in 3x parts of 100MB to make it fit, and can't move current data. (By the way, this is not a Windows limitation, this is a computer limitation. It affects: Android, iOS, MacOS, all Linux distros, etc. It needs to defragment the free space. In order to do this, it needs to switch stuff up between the page file and RAM, as this is the only way to defragment the RAM to have back that 1 GB of free space as 1 free block.

 

This is why pagefile should NEVER be disabled. Windows Vista and up favors your RAM in any case, so there is no point to disable it. The example mentioned, is a simple one, but program can expand its memory usage, like you load a project file in a program. If you don't have the page file, you can see Windows bugging you about "Low virtual space" when you are low in RAM (even if you have in total lots of it, as you don't see the actual layout of the RAM, but Windows knows it), and if you don't have enough for a program to expand or open, expect crashes.