The truth about pagefile (SSD)

[hellopaul_1-fV1Lg4]

Good afternoon!

Two years ago you guys (especially Harm) helped me to build a PC for Premiere. After two years I had to update my disks setup and decided to buy a Samsung 830 SSD for OS. Now, after I've read tons of informations about how to setup the drive, I know nothing...

As I remember, and as I checked on this forum, if you have 4 disks setup, you should set your pagefile on any other disk but OS disk - especially if You work in Photoshop, which uses pagefile a lot. This statement was totally ok for me until I found these:

Quote :

You don't need a pagefile at all with 8 gigs of RAM -- turn it off.

"This may be true, but it could also cause grief.   Each user is different, and it's dangerous to make generalizations such as this because people use different amounts of RAM depending on the combination of programs and documents/files that they have open at any one point in time.

To find out how much pagefile you need, run Task Manager (Ctrl+Shift+Esc) and click the "Performance" tab.   The "Memory" bar graph (to the left of the "Physical Memory Usage History" graph) shows how much memory you're using.   Start up all the programs you might possibly run at the same time and use them to open the biggest documents/files/photos/movies that you may ever have open at once. Note the amount of RAM in the bar graph and add perhaps 25% to 50% as a safety margin.   For example, if your bar graph shows 6GB, then you'd probably be safe in assuming that you need no more than 8GB of memory."

And MORE IMPORTANT:

"Do you understand what happens to an SSD that has run out of write cycles on it's NAND? It becomes read-only memory. It doesn't simply stop working. I work in manufacturer's SSD R&D (who also makes much of the NAND used in many SSD's) and while typical "current" 25nm and 34nm MLC is rated between 3000-5000 write cycles, it is "conservatively" rated as such.  Neither you or any of your friends who work with Photochop or Win Temp files are blowing through this many write cycles in a 6 month period without doing "other" much more destructive writing.

In fact it's extremely rare that any SSD has all of it's write cycles burned up. It is FAR more likely that there is a controller failure from firmware or other electrical burnouts/failures, that have nothing to do with the number of write cycle endurance left in the NAND. Even in our labs running 24x7 weeks-long full write tests, which is a thousand times more intensive than photoshop or win pagefiles, we rarely use up all the write cycles of the NAND before other failures occur. While these "other" (aka non NAND write-endurance related) failures suck when they happen, it has nothing to do with anything photoshop or win pagefiles is going to make occur faster or slower.

If your "friends" are buring out current SSD's in 6 month periods, they are either buying crappy SSD's, doing odd things to the SSD's, or simply have failures they are blaming erroneously on NAND write cycle limitations.  Don't get me wrong, SSD's will fail, but unfortunately, very rarely will the failure be from write cycle endurance life of the NAND, and definately not because the SSD is used with photshop scrathdisks or win pagefiles.

To use a unpopular automotive analogy, the NAND write cycle life is like the engine of a car that is used where they use salt on the roads to melt ice. While it is possible for the engine to die from being used too much, it is much more likely the body of the car is going to rust/rot away before the engine has outlived it's useful life. And this car does not care if photoshop or win temp files are in the passenger seat. If the SSD fails under 2-3 years of normal use, it won't be because of photoshop or win pagefiles using up the NAND write cycles. "

As I understand, this guy (who actually produces SSDs) says that firstly -  you CAN set your pagefile on SSD - and secondly - you do NOT need to set up a pagefile for photoshop at all.

Now I am REALLY confused... I trust Harm and I trust all of your expierence guys and would be very thankful for any information about this.

P.S. After I bought the SSD I found out that my MB has crappy Marvell SATA3 Controller... 😕

My setup is:

GA-X58-UDR3

i7 930 @3.8Ghz

G.Skill Dual ECO 1.35v CL8 12GB

GeForce GTX460

Samsung SSD 830 128GB

Samsung F3 Spinpoint 2x1TB

WD something 160GB (just for backup or trash)

Regards,

Paul

[Jim_Simon]

Finally, some sanity about the page file.

Just leave it alone, I say.  Let Windows manage it, which is the default arrangement when you install the OS.  This is NOT something that needs tweaking, and could possibly cause issues if you don't tweak it correctly.

[Harm_Millaard]

Windows8 and possibly Windows7 - I'm not sure about Win7 - will create a pagefile in case of a system hang for the memory dump and it will create that on the C: drive, even if you have a pagefile on another drive. Windows will only start if there is a pagefile. If there is no pagefile defined, it will automatically create a dynamic one on the C: drive.

With these two items as a given, the question remains, what is wise. Jim always says let Windows decide, so his suggestion is a dynamic page file.

Pagefiles are a relic of the past, dating back to the times when memory was scarce, only 2, 4 or maybe 8 GB memory and at that moment the rule was to use up to 1.5 to 2.0 x  the amount of memory for the pagefile, a rule Windows still adheres to in its default setting. With systems now abundant that contain 32 or even 64 GB of memory, that no longer holds. You will have a difficult time to run PR where it uses more than 24 GB of memory, let alone 48 or more GB's. (AE is a different matter).

So, IMO we have to lose the old and outdated assumption that it is best to use a pagefile with a size of 1.5 or 2.0 times the physical memory. It no longer holds true. I think that a sum total of physical memory plus pagefile amounting to around 64 GB is more than enough for most cases. So I suggest the following rule of thumb for your pagefile, depending on your use of PR and AE, the nature of your source material and the complexity of your timelines:

• With less than 32 GB installed, use a static pagefile of X GB to bring the sum total up to 32 - 48 GB.
• With 32 GB installed, use a static pagefile of 32 GB to bring the sum total up to 64 GB.
• With 64 GB installed, use a static pagefile of at least 1 GB, but no more than 16 GB. Everything more is a waste of space.

I intentionally mention STATIC pagefile, in contrast to Jim's suggestion, who pleads for dynamic pagefiles for the following reason:

Every time the pagefile changes its size, under Windows direction, it not only means that the data changes, but also that the file allocation table at the beginning of the disk needs to be rewritten to reflect the changed size. Every alteration in file size thus requires extra writing to the SSD, reducing its limited lifespan and leads to fragmentation of that pagefile. A static file does not have these negative consequences. Only data need to be written in the file, no alterations to the file allocation table need to be made. And Windows does not need to keep logs of those changes, further reducing the need to write additional data.

For example, if your bar graph shows 6GB, then you'd probably be safe in assuming that you need no more than 8GB of memory.

It is pretty easy with only Premiere Pro open and playing back a timeline to reach 24 GB memory use. Now add a few other applications and it is safe to say you need 32 GB memory at least, so with 8 GB memory, you need to add a pagefile of 24 GB or more.

[Jim_Simon]

Every time the pagefile changes its size, under Windows direction, it not only means that the data changes, but also that the file allocation table at the beginning of the disk needs to be rewritten to reflect the changed size. Every alteration in file size thus requires extra writing to the SSD, reducing its limited lifespan and leads to fragmentation of that pagefile.

Two things.  First, the size of the page file is only going to change if Windows needs to make it larger, which as you previously pointed out isn't going to be very often, if ever, with larger amounts of RAM.  And second, like the article says, the SSD will wear out from other factors long before it ever wears out from too many page file reads/writes.

That's why I recommend leaving it alone.  It just isn't a necessary tweak.

A static file does not have these negative consequences.

The one negative consequence it does have is that in the rare event the page files does need to be made larger, you're screwed.

So in the end, what we have are no actual negatives for leaving it alone, and one very real possibile negative for changing it.

[Harm_Millaard]

The one negative consequence it does have is that in the rare event the page files does need to be made larger, you're screwed.

In what way? Does the system hang? No. Does it no longer work? No. Does it get slower? Yes. How often does that happen? Around never.

[El_Plates]

How do we know when our computer is writing to pagefile ?

[hellopaul_1-fV1Lg4]

When Windows is using more than 90% of your RAM it creates the pagefile (virtual memory), I think

[Jim_Simon]

The one negative consequence it does have is that in the rare event the page files does need to be made larger, you're screwed.

In what way? Does the system hang? No. Does it no longer work? No.

Yes, that can happen.  If Windows needs to write to swap, and there is no room for it, you can end up with a crash.  Windows doesn't "use regular disk space" for paging.  It uses the defined paging sectors.  And if it needs more than is available and can't create more on the fly, then you crash.

This is why I recommend leaving the page file alone.  There is no disadvantage in doing so, but there is the potential for bad things if you do change it.

[Harm_Millaard]

Jim,

With Win7 I did rather extensive tests with static pagefiles, ranging from 16 MB to large sizes and ran memory hungry applications on a system with only 12 GB memory and NEVER experienced a crash when the pagefile was 100% utilized and the system demanded more.

[hellopaul_1-fV1Lg4]

First of all, I'd like to thank You guys for Your time and effort.

Second of all, as far as I understood:

- pagefile is a file that gets in use when system needs more RAM than it's available

- in 90% of times the only programs that could use more than 12GB ram are Adobe programs (I mean, heavy processing programs like PR, AE PS etc)

- if I have only 12GB of RAM installed, I should set my statis pagefile to 20GB minimum or I should use a dynamic pagefile if  Jim's Simon statement turns out to be true

The one negative consequence it does have is that in the rare event the page files does need to be made larger, you're screwed.

In what way? Does the system hang? No. Does it no longer work? No. Does it get slower? Yes. How often does that happen? Around never.

Now, what could possibly happen if I don't set any pagefile? As I understood, Windows will create a pagefile by his own, right? And if any program would need more than 12GB of my RAM, my system would hang, right? If this is what gonna happen, I'm totally OK with setting the pagefile to 20GB.

Now, how this 20GB pagefile could affect my new SSD? 'Cause I think this is the most important question here - should we let create a pagefile on system drive (SSD) or just put it on some other fast drive? As this SSD's manufacturer says, we could easly use a SSD.

Have a nice weekend!

[Harm_Millaard]

Windows always requires a pagefile, even if you have not defined one. It will automatiocally create one if none is found at boot time. In size it can vary from 16 MB to 64 GB or even more.

If the pagefile is fully used and there is no more space it either allocates the space for it, increasing the size of the file in the case of a dynamic (Windows default) file, or it uses the regular disk space to store intermediate results. This makes the system slower, but it does not hang the system.

If you have a SSD as a boot drive, put it there.

[hellopaul_1-fV1Lg4]

Thank You Harm for clearing this out.

One last question: what if my SSD is only 128Gigs and my system + a few programs take most of it? Should I still try to fit 20Gigs pagefile on SSD or set it on Samsung F3?

[Harm_Millaard]

First of all, a SSD does not suffer from fill-rate degradation. Second, if I look at my three year old system - and you have no idea what kind of stuff you collect in three years - with Master Collections CS5, CS5.5 and CS6 installed plus all the plug-ins, testing tools, benchmarking programs, the PPBM5 and PPBM6 websites, and a whole lot of other stuff, I only use less than 80 GB of space, even though my pagefile is on another disk on this old system, so I think 128 GB should be more than enough.

One hint. Even though Google Chrome is popular and very fast, it has the distinct disadvantage that it stores everything in your user profile, in contrast to Mozilla Firefox and Internet Explorer, both putting less strain on your SSD. Using Firefox is less demanding on your system and storage than Google Chrome, because of this weird behaviour. This only holds if there is more than one user on the system.

[petrtyl1]

If it helps, I have a Crucial M4 128 GB SSD with the pagefile on it.  Below is a screenshot of Crystal Disk Info showing that despite 2229 hours of use, I still have 99% of the drives rated lifetime left.  Anandtech has several good articles about what it takes to wear out an SSD.