Disable/Limit Windows File System Cache in favor of FC

[mgb]

I'm running WinXP 32-bit on a machine with 8GB of RAM, and have dedicated the upper 4GB to FancyCache.

Since I have so much RAM dedicated to FancyCache caching, I would like to completely disable Windows File System Cache, which consumes memory below the 3.2GB line, and instead force all I/O to go directly through FancyCache.

Is there a way to do this?

[Support]

Well, currently we don't recommend it. Also I haven't found a way...

[theNige]

While I believe you won't want to disable any core windows function, there *might* be a way to reduce the amount of memory that Windows uses for caching .

I use Windows 7, and it still contains registry entries for LargeSystemCache and Size - both of which will influence memory usage.

On the premise these still work as designed, I set them to 0 and 1 respectively.

See link below:

http://technet.microsoft.com/en-us/libr ... 10%29.aspx

I have not done any real benchmarks as I have 16Gb of memory and am still testing various FC parameters on the 3 HDs I have installed.

Cheers,
Nigel

[mgb]

Thanks for the input, theNige. I was aware of LargeSystemCache, and is currently set to the default of zero. The Size setting looks interesting, although it seems like it might have more impact on network file sharing than on local file system caching. Either way, the setting is present on WinXP Pro, and is set to 2 by default. A value of 1 looks promising.

[MrCache]

I must say I'm still rather amazed at the number of people that completely fails to understand how Windows file caching works. Everywhere I read about people wanting to disable it, force it to use less ram and so on. Read this and learn, once and for all, how Windows file caching works.

Windows caches files in free ram. Yes it may use several gigabytes of ram for filecaching, but that's a good thing. Why, do I hear people ask, is it a good thing that Windows is using up all my ram for caching files?

Well, understand this - ram used for caching files is considered "free to use" by the os, should the need arise that an application needs more ram. Any files cached in ram is simply purged if/when ram is needed. This happens instantly - yes, instantly!

Some even believe that Windows filecaching causes paging, and that Windows will page the cached content to the pagefile if ram is needed by applications, causing a slowdown. Wrong, wrong, wrong!

So if anything, you could say that in order to have Windows perform at absolute maximum performance, you'd want 0 free ram all the time, and you'd want as many files cached into ram as possible, since, as I said above, if ram is needed by applications, Windows will imidiately flush memory used by cached files to make room for the apps.

That's also a reason why all these "free-ram" applications are snake-oil, that will do nothing but slow down the system.

[mgb]

Despite the sarcasm, your description is basically correct, however It does not support the assertion that disabling the Windows File System Cache is inappropriate in every case.

I have 8GB of memory in my machine, over 4GB of which is inaccessible to WinXP. However FancyCache CAN make use of that memory to cache file system data. In this mode, there is no value in WinXP re-caching that same file system data below the 3.2GB line. Windows File System Cache is not providing any value - it is just one more stop my data must make on the way from the disk to my application, and is therefore slowing things down (albeit marginally). If it CAN be turned off, I'd like to turn it off. If not, oh well.

[MrCache]

The difference is that the "regular" windows file cache in this case is faster than the L2 cache used by fancycache when utilizing memory above the ~3.5 gigabyte limitation put in place by 32-bit Windows. In no way do the normal filecache slow things down, I don't understand why you believe that to be the case?

[mgb]

It's simply that the "regular" windows file cache is one more cache in the chain. Since my goal is to leverage the 4GB above the line, I'm dependent on FancyCache's L1 and L2 caching mechanism. I would prefer that my application be able to issue a read request and have FancyCache immediately step in and satisfy the read, dispensing with the effort WinXP is putting forth maintaining another cache.

In the end, it's not a significant resource consumer - in fact, I'll probably never make back the time I've spent searching for a way to turn off the cache. It's just my endless quest for optimal performance.

[Violator]

Just leave it at it's default, it's not like those few MB matter.

Something you can disable thou: http://msdn.microsoft.com/en-us/library ... .5%29.aspx
You can also disable some services and stuff, but for that you need to do a lot of reading and testing, there isn't a one size fits all recipe for that.
You can also try Iobit's GameBooster 3 Pro Beta, safer way to disable services etc. and restore them to their default values if something breaks.

And of course http://support.microsoft.com/kb/259716 Keep in mind that some applications require it to be enabled!

[secured2k]

I don't think you can disable the cache feature. You can configure the cache using some programming APIs in Windows. There is a program for this called CacheSet that might be what you are looking for.

http://technet.microsoft.com/en-us/sysi ... 97561.aspx