Enabling/Disabling LargeSystemCache with Windows 7 on SSD

I was doing some research on making my SSD run smoother and I came across a website that had a list of 12 things to do if you have a SSD:

12 Things You Must Do When Running a Solid State Drive in Windows 7

Most of these I had already done in the past, but the one that threw me off was disabling the largesystemcache. I didn't know that this was even a thing until I saw it here and I noticed that a program called SSD Tweaker has it as an option to disable it as well. When I went into the registry, I noticed that the value was set to 1. I'm not sure why it was or why a program would need to turn it on, but I set it to 0 since the site and the program suggested it, and because it's the default setting in a fresh install of Windows.

I was just curious as to how other people have it setup or if they can give a little more information about the feature.

The default value for LargeSystemCache is 0. It is normally enabled (set to 1) only on servers or client systems used primarily as servers. It was not intended for general use. I am not convinced it is even supported in Windows 7. In supported systems it would allow the file cache to grow to the point where applications ran short. On a server that is a good thing because a large file is good when sharing files on a network and nobody cares how well applications run on a server. But in a system used primarily to run applications that would be a bad thing. Leave it at 0.

In XP days there were many "tweaking" sites that had this hopelessly wrong, and many more things besides.

The default value for ClearPageFileAt Shutdown has always been 0 and is appropriate for most situations. Unless your computer contains particularly sensitive information setting it will make little sense.

I wouldn't disable the pagefile unless disk space was desperately short, in which case you would need a bigger disk. The pagefile is designed to optimize performance and it usually does. Modern SSDs do have limited writes but you would have to really work at reaching it. Most SSDs die of other causes long before limited writes becomes a problem, or more commonly the drive is replaced because it is too small.

I have disabled the pagefile on C: (SSD) and enabled on D: (HDD) with size set twice my memory (min=Max). Works very well.
As I have moved \Users to D: during installation, the %USERPROFILE%\AppData\Local\Temp is on the D: and I have changed the Temp and TMP from Windows\Temp to D:\Temp, all temporary files (from windows and from user) are now on the HDD.

LMiller7 said:

The default value for LargeSystemCache is 0. It is normally enabled (set to 1) only on servers or client systems used primarily as servers. It was not intended for general use. I am not convinced it is even supported in Windows 7. In supported systems it would allow the file cache to grow to the point where applications ran short. On a server that is a good thing because a large file is good when sharing files on a network and nobody cares how well applications run on a server. But in a system used primarily to run applications that would be a bad thing. Leave it at 0.

In XP days there were many "tweaking" sites that had this hopelessly wrong, and many more things besides.

The default value for ClearPageFileAt Shutdown has always been 0 and is appropriate for most situations. Unless your computer contains particularly sensitive information setting it will make little sense.

I wouldn't disable the pagefile unless disk space was desperately short, in which case you would need a bigger disk. The pagefile is designed to optimize performance and it usually does. Modern SSDs do have limited writes but you would have to really work at reaching it. Most SSDs die of other causes long before limited writes becomes a problem, or more commonly the drive is replaced because it is too small.

Got it. I'll just leave both of them at zero. How does trim work? I know that it is enabled on my system, but what does it mean when trim is enabled? Does something run in the background on a schedule to trim the ssd?

Megahertz07 said:

I have disabled the pagefile on C: (SSD) and enabled on D: (HDD) with size set twice my memory (min=Max). Works very well.
As I have moved \Users to D: during installation, the %USERPROFILE%\AppData\Local\Temp is on the D: and I have changed the Temp and TMP from Windows\Temp to D:\Temp, all temporary files (from windows and from user) are now on the HDD.

I have my system setup the same way. I don't see my system using the pagefile often. The only time I see it using the pagefile is when I'm playing a game that uses a lot of memory, like PUBG, but even then, it only uses less than 1000 MB and I have my pagefile system managed, but it seems to use 15.86 GB all the time.

TONPumper said:

I have my system setup the same way. I don't see my system using the pagefile often. The only time I see it using the pagefile is when I'm playing a game that uses a lot of memory, like PUBG, but even then, it only uses less than 1000 MB and I have my pagefile system managed, but it seems to use 15.86 GB all the time.

There are tonnes of tutorials on internet giving suggestions regarding to move the pagefile or not and in my opinion there is a battle of different "opinions" (or fanbois) regarding the effects of moving the file.
I just leave the pagefile where is because by the time my SSD will die, we will have newer technology and cheaper drives (or memory chips) on the market.

The idea that the LargeSystemCache setting would load the kernel in RAM is nonsense. It was likely based on misunderstandings piled on misunderstandings. Microsoft documentation makes no mention of this and it is clearly impossible. The kernel itself is always loaded in RAM. Code must exist in RAM before it can be executed. The kernel manages paging so if the kernel itself was not resident in RAM how could it manage anything?

The setting would potentially result in a larger file cache. In itself that is a good thing. But what the tweaking sites always seemed to miss was that this came at a price. Since memory was limited more memory used for the file cache meant that there was less available for applications. By default (with the setting at zero) the system memory manager would balance the size of cache and application memory to maximize application performance. In a client OS that is what you want.

But in a file server things are different. A file server exists to share files on the network and this is the aspect of performance that matters. A file server runs few applications, such as for making backups and other utilities and their performance is is minor concern. The LargeSystemCache setting upset the balance so as to favor the file cache, even to the point where applications ran short of memory. This is a good thing, but only in a computer used primarily as a server.

I used the setting on a computer running Windows 2000 server. I noticed no difference in performance with it on or off. I have also tried "DisablePagingExecutive" with no difference in performance. I am not convinced that either is even supported in a modern OS.

Microsoft did warn that some third party device drivers behaved very badly in a system where the setting was on and data corruption could result.