[jr2]

...All these were products to increase memory by compressing it (well, SoftRAM was a placebo and didn't actually do anything).

Well, for those not in the loop:

Android 4.4 +

OS X Mavericks +

Windows 10 build 10525 +

All use memory compression.

Now why couldn't they have had this built into XP back when whiny customers were complaining about slow computers running XP with 128 or 256 MB RAM?  Wouldn't have helped much, but it would have helped some! 

Anywho, just thought that was interesting to see that tech finally implemented wide scale.

Source:

https://en.wikipedia.org/wiki/Virtual_memory_compression#Recent_developments

Or just read the whole article, it's interesting (sort of).

[headdie]

God, you just took me back to the 90s and not in a good way lol.

Did any of them actually work without killing response times?

[The E]

Now, before you get all giddy about this, here's the limitations of this tech:

1. It will only work on unused pages. This means that RAM pages that are slated to be paged out into the disc cache will be compacted and kept in memory a bit longer.
2. A side effect of this is that since these pages are kept as part of the System process memory, for an outside observer it will look like Win 10 just consuming more RAM.
3. Basically, this does not help you if you're running on a system with not enough memory.

[Phantom Hoover]

This seems like a really bad trade, of memory latency in exchange for capacity. Getting more RAM than you need is pretty easy these days, expanding the bottleneck between RAM and the CPU is not.

[Polpolion]

This seems like a really bad trade, of memory latency in exchange for capacity. Getting more RAM than you need is pretty easy these days, expanding the bottleneck between RAM and the CPU is not.

Going by what The E said this is not meant to make physical memory go farther, it's just meant to reduce the cost of page misses at the cost of some available physical RAM.

[Bobboau]

yeah, it actually is an optimization to lessen latency.

[Phantom Hoover]

Ah, it speeds up paging to the disk (from incredibly slow to somewhat-credibly slow). Contrary to what The E said I can't see that being useful on anything but low-memory systems.

[jr2]

It would be useful for the same reason it's not recommended to disable the swap file.  Some programs utilize the swap file, even if they have all the yottabytes of RAM they could wish for.  I don't know why, but that's what I've read.

[The E]

Then you probably read wrong (or whoever wrote it was wrong), because there is no conceivable reason why a programmer would deliberately write stuff into swap (Off the top of my head, I am not even sure that doing so is possible, this sort of stuff is left for the OS to figure out for a reason).

[Polpolion]

It would be useful for the same reason it's not recommended to disable the swap file.  Some programs utilize the swap file, even if they have all the yottabytes of RAM they could wish for.  I don't know why, but that's what I've read.

What you probably read was that the page file sometimes gets written to even if there is available physical ram, something that is handled by the operating system, probably when it thinks it would rather have a page of physical memory free than underutilized. Don't quote me on that though. Windows and Linux have pretty different philosophies about this stuff, and a lot of it the user doesn't see.

[jr2]

http://unix.stackexchange.com/questions/190398/do-i-need-swap-space-if-i-have-more-than-enough-amount-of-ram

Good response here:

Yes.

You should most definitively always have swap enabled, except if there is a very compelling, forbidding reason (like, no disk at all, or only network disk present).

The reason is that swap is not only useful when your applications consume more memory than there is physical RAM (actually, in that case, swap is not very useful at all because it seriously impacts performance). The main incentive for swap nowadays is not to magically turn 16GiB of RAM into 32 GiB, but to make more efficient use of the installed, available RAM.

On a modern computer, RAM does not go unused. Unused RAM is something that you could just as well not have bought and saved the money instead. Therefore, anything you load or anything that is otherwise memory-mapped, anything that could possibly be reused by anyone any time later (limited by security constraints) is being cached.
Very soon after the machine has booted, all physical RAM will have been used for something.

Whenever you ask for a new memory page from the operating system, the memory manager has to make an educated decision:

• Purge a page from the buffer cache
• Purge a page from a mapping (effectively the same as #1, on most systems)
• Move a page that has not been accessed for a long time -- preferrably never -- to swap (this could in fact even happen proactively, not necessarily at the very last moment)
• Kill your process, or kill a random process (OOM)
• Kernel panic

Options #4 and #5 are very undesirable and will only happen if the operating system has absolutely no other choice. Options #1 and #2 mean that you throw something away that you will possibly be needing soon again. This negatively impacts performance.
Option #3 means you move something that you (probably) don't need any time soon onto slow storage. That's fine because now something that you do need can use the fast RAM.

By removing option #3, you have effectively limited the operating system to doing either #1 or #2. Reloading a page from disk is the same as reloading it from swap, except having to reload from swap is usually less likely (due to making proper paging decisions).

In other words, by disabling swap you gain nothing, but you limit the operation system's number of useful options in dealing with a memory request. Which might not be, but very possibly may be a disadvantage (and will never be an advantage).

However, the traditional recommendation of making swap twice the size of RAM is nonsensical. Although disk space is cheap, it does not make sense to assign that much swap. Wasting something that is cheap is still wasteful, and you absolutely don't want to be continually swapping in and out working sets several hundreds of megabytes (or larger) in size.

There is no single "correct" swap size (there are as many "correct" sizes as there are users and opinions). I usually assign a fixed 512MiB, regardless of RAM size, which works very well for me. The reasoning behind that is that 512MiB is something that you can always afford nowadays, even on a small disk.
On the other hand, adding several gigabytes of swap is none better. You are not going to use them, except if something is going seriously wrong.

Even on a SSD, swap is orders of magnitude slower than RAM (due to bus bandwidth and latency), and while it is very acceptable to move something to swap that probably won't be needed again (i.e. you most likely won't be swapping it in again, so your pool of available pages is effectively enlarged for free), if you really need considerable amounts of swap (that is, you have an application that uses e.g. a 50GiB dataset), you're pretty much lost.
Once your computer starts swapping in and out gigabytes worth of pages, everything goes to a crawl. So, for most people (including me) this is not an option, and having that much swap therefore makes no sense.

5       
Completely untrue: it could be an advantage for the kernel to not use the disk, especially if you have configured OOM to your specs. If the OOM killer is configured to handle your cleanup, then having it do so rather than wasting disk space and slowing your machine down is advantageous. –  mikeserv Mar 16 at 16:22

11       
What's the difference between having 8 GB of RAM and 8 GB swap and 16 GB of RAM and no swap? If your computer decides it needs 16.001 GB of memory, won't it start purging/killing things just the same (but the performance will crater before it starts happening)? –  Nick T Mar 16 at 19:10

4       
@NickT: The swap isn't for more RAM so much as a red flag that something is going to get killed soon. I like having a red flag before a kill, rather than having a process "randomly" disappear before my eyes. –  Mooing Duck Mar 16 at 19:34

5       
-1 this answer makes no sense. Why the heck would having slower memory (swap) have better performance than the same amount of faster memory (RAM)?? at some point you have to acknowledge enough RAM means no swap is necessary.. –  Mehrdad Mar 16 at 20:23

8       
@Mehrdad: It certainly does make sense. Slower memory (swap) improves performance insofar as "slower" does not matter for things that you access rarely or never. Swap effectively increases the amount of memory that is available for "hot" data by moving "cold" data out. Daemons which only execute something once per hour or memory allocated by a kernel module that is loaded by default but never used are an example of that. You can swap out those, or you can instead drop pages from the cache. Which one is better? –  Damon Mar 16 at 20:32

That was Unix-oriented, but for Windows, the advise is the same:

http://www.howtogeek.com/126430/htg-explains-what-is-the-windows-page-file-and-should-you-disable-it/

HTG Explains: What is the Windows Page File and Should You Disable It?

Windows uses a page file to store data that can’t be held by your computer’s random-access memory when it fills up. While you can tweak the page file settings, Windows can manage the page file fine on its own.

The Windows page file is somewhat misunderstood. People see it as the cause of slowdowns because it’s slower to use the page file than your computer’s RAM, but having a page file is better than not having one.

How The Page File Works

The page file, also known as the swap file, pagefile, or paging file, is a file on your hard drive. It’s located at C:\pagefile.sys by default, but you won’t see it unless you tell Windows Explorer not to hide protected operating system files.

Your computer stores files, programs, and other data you’re using in your RAM (random access memory) because it’s much faster to read from RAM than it is to read from a hard drive. For example, when you open Firefox, Firefox’s program files are read from your hard drive and placed into your RAM. The computer uses the copies in RAM rather than repeatedly reading the same files from your hard drive.

Programs store the data they’re working with here. When you view a web page, the web page is downloaded and stored in your RAM. When you watch a YouTube video, the video is held in your RAM.

When your RAM becomes full, Windows moves some of the data from your RAM back to your hard drive, placing it in the page file. This file is a form of virtual memory. While writing this data to your hard disk and reading it back later is much slower than using RAM, it’s back-up memory – rather than throwing potentially important data away or having programs crash, the data is stored on your hard drive.

Windows will try to move data you aren’t using to the page file. For example, if you’ve had a program minimized for a long time and it isn’t doing anything, its data may be moved to RAM. If you maximize the program later and notice that it takes a while to come back instead of instantly snapping to life, it’s being swapped back in from your page file. You’ll see your computer’s hard disk light blinking as this happens.

With enough RAM in modern computers, the average user’s computer shouldn’t normally use the page file in normal computer use. If you do see your hard drive start to grind away and programs start to slow down when you have a large amount open, that’s an indication that your computer is using the page file – you can speed things up by adding more RAM. You can also try freeing up memory — for example, by getting rid of useless programs running in the background.

Myth: Disabling the Page File Improves Performance

Some people will tell you that you should disable the page file to speed up your computer. The thinking goes like this: the page file is slower than RAM, and if you have enough RAM, Windows will use the page file when it should be using RAM, slowing down your computer.

This isn’t really true. People have tested this theory and found that, while Windows can run without a page file if you have a large amount of RAM, there’s no performance benefit to disabling the page file.

However, disabling the page file can result in some bad things. If programs start to use up all your available memory, they’ll start crashing instead of being swapped out of the RAM into your page file. This can also cause problems when running software that requires a large amount of memory, such as virtual machines. Some programs may even refuse to run.

In summary, there’s no good reason to disable the page file – you’ll get some hard drive space back, but the potential system instability won’t be worth it.

Code: [Select]

Managing the Page File
Windows automatically manages the page file’s settings for you. However, if you want to adjust your page file settings, you can do so from the Advanced System Settings window. Click Start, type Advanced System Settings into the Start menu and press Enter to open it.

Click the Settings button under performance.

Click over to the Advanced tab and click the Change button in the Virtual memory section.

Windows automatically manages your page file settings by default. Most users should leave these settings alone and allow Windows to make the best decision for you.

However, one tweak that may help in some situations is moving the page file to another drive. If you have two separate hard drives in your computer, assuming one is the system drive with your programs installed on it and one is a less-used data drive, moving the page file to the data drive can potentially offer some increased performance when your page file is in-use. Assuming that Windows will already be using the system drive if it needs to use the page file, this spreads out the hard drive activity instead of concentrating it on one drive.  {note you may have multiple "drives" that are just partitions on the same disk, so you might not get any performance increase from doing this; also, maybe your data drive is a slower model?  Check your specs, and Disk Management, to be sure ~jr2}

Note that this will only help if you actually have two separate hard drives in your computer. If you have one hard drive separated into multiple partitions, each with their own drive letter, this won’t do anything. Whether it’s partitioned or not, it’s still the same physical hard drive.

In summary, the page file is an essential part of Windows. Even if it’s rarely used, it’s important to have it available for situations where programs are using an unusually large amount of memory.

Having a page file won’t slow down your computer – but if your computer is using its page file a lot, you should probably get some more RAM.

Opposing view:

http://superuser.com/questions/30345/any-reason-not-to-disable-the-windows-pagefile-given-enough-physical-ram

Any reason not to disable the Windows pagefile given enough physical RAM? [closed]

up vote {34} down vote

The question of disabling the Windows pagefile has already been discussed quite a bit, for example here and here and here. People continue to upvote answers that say "you should not disable your pagefile even if you have plenty of RAM", but I have yet to see any concrete, verifiable reasons being given for this advice. As far as I can see, if you never need to read from the pagefile (because you have enough RAM) then performance could only be worse with it enabled due to Windows pre-emptively writing to it. At best, performance would be the same. I can't see how it could possibly be improved by writing data you never need to read.

So my question is:

Assuming that I have enough physical RAM for everything I do, is there any reason I should not disable the pagefile?

Let's say the version of Windows is Windows XP x64 SP2 or Windows Server 2003 x64 SP2 (same thing). If it's different for Windows Server 2008 x64 I'd be interested to hear an answer for that as well. I'm looking for specific, objective reasons from good sources, not just opinions. Something like "here are the benchmarks done with and without a pagefile and the results were better with a pagefile, even with enough RAM" or "according to this MS KB article problem X occurs if you disable the pagefile".

So far the only reasons I've seen mentioned are:

• Even if you think you have enough RAM you might run out. OK, but for the purposes of this question, let's just take it as a given that I have enough. Maybe I only ever read my email and I have 16GB RAM. Or 128GB. Or 1TB. Or whatever - but it's enough for 100% of what I do, 100% of the time. Another way to think of it is: if I have x MB physical RAM and y MB pagefile and I never run out of RAM in that configuration, would I not be better off, performance-wise, with x+y MB physical RAM and no pagefile?
• Windows is "used to" having a paging file and it might not function as reliably (from Understanding the Impact of RAM on Overall System Performance) That's rather vague and I find it hard to believe, given that MS has provided the option to disable the pagefile.
• Windows knows what it's doing better than you. No - it doesn't know that I won't run more programs or load more data, but I do.

closed as not constructive by Tom Wijsman, Sathya♦ Feb 18 '11 at 13:28

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
If this question can be reworded to fit the rules in the help center, please .

   
14       
this subject has been discussed ad nauseam in pretty much every tech related forum under the sun. conclusion: do it or don't do it. if it works for you, great, get on with your life. if it doesn't, well, virtual memory just a few mouse clicks away. other than that, we're wasting our time here. better off to discuss the best browser or antivirus software! (btw, that link of yours is a great read, recommended) –  Molly7244 Aug 26 '09 at 23:49

I don't think this is worth its own answer, but be aware that data stored in RAM can be less reliable than data stored on disk. I've seen reports of corruption using RAM disks. RAM is volatile, disk is not. For caching data and preserving it for later use, writing it to disk gives you a minutely better chance of avoiding corruption than the tiny change of it occurring with in-RAM caching. –  ssube Sep 9 '10 at 4:26

1       
I feel your frustration on this.i recently went from 4gb of ddr2 to 8gb of ddr3. A guy at work says "be sure to make your swap size 8-12gb". WHY? Im doing the same stuff I was doing before, and now I have twice as much physical ram; why would I need MORE swap space? –  LoveMeSomeCode Feb 12 '11 at 21:14

2       
Not subjective - please read the question carefully, particularly the assumption. I'm asking for specific reasons from reliable sources, not opinions. –  EMP Feb 17 '11 at 4:55

   
Dupe of: Windows Swap (Page File): Enable or Disable? –  Ƭᴇcʜιᴇ007 Aug 25 '11 at 20:04

   
tweakhound.com/2011/10/10/… –  Kokizzu Jan 19 '13 at 17:20

Answers:

up vote 15 down vote
This is a micro-optimization. The point is that there's no reason to do it, in anything resembling normal operation. It could easily hurt you if your usage pattern changes.

In specialized cases it might make sense, such as if there is no local writeable disk.

up vote 8 down vote
From this link:

NOTE: Microsoft strongly recommends that you do NOT disable or delete the paging file.

To disable the use of the paging file in Windows XP, you should have at least 768MB of RAM.

Here's a link to Jeff Atwood's take on it.

up vote 8 down vote
There are many reasons to keep the pagefile even if you can fit everything into RAM.

The answer on SF has 125 upvotes and links many credible articles. Check it out:

http://serverfault.com/questions/23621/any-benefit-or-detriment-from-removing-a-pagefile-on-an-8gb-ram-machine/23684#23684