Windows: Disable caching of large files

Question

I am currently dealing with very large video files, including de/encoding them and copying them around etc.

To my surprise Windows attempts to cache these video files, even though there is no point in doing so. They're far too big to be cached. (Up to 230 Gigabyte.)

I am also shocked by the fact that Windows is almost completely clearing the normal contents of the cache for the video files. It is desperately trying to cache them, making my system pretty slow.

How can I tell Windows not to cache these files? If that is not possible, are there other ways to deal with this problem?

Answer 1

Using Cacheset.exe from the Sysinternals Suite by MS solved the problem for me. Remember to run it as administrator, otherwise it will tell you that the values you entered are invalid.

Normally, caching the files should not be a problem, pushing other contents of the RAM out is. Check if you have the LargeSystemCache setting in HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management set. I suspect this is the real cause of the "clearing everything else" behavior. (My system was swapping out active processes while trying to cache a video I was encoding with avidemux).

Answer 2

I'm pretty sure what you're observing can't and shouldn't be disabled.

Every application can decide for itself to map a file into memory. And, to my understanding, that can drastically improve performance.

And, as you can see in your screenshot, the 4GB are already on Standby. Meaning they aren't actually any longer in use and can be re-assigned to new processes.