CacheSet

CacheSet is an applet which helps you manipulate the working-set parameters of the system file cache. Unlike CacheMan, CacheSet runs on all versions of NT and will work without modifications on new Service Pack releases. In addition to providing you the ability to control the minimum and maximum working set sizes, it also allows you to reset the Caches working set, forcing it to grow as necessary from a minimal starting point. Also unlike CacheMan, changes made with CacheSet have an immediate effect on the size of the Cache. Full source code is included.
Use CacheSet to performance tune the system Cache size in a way not possible without tweaking internal variables the way CacheMan does.
Note: To use CacheSet on NT 4.0 Service Pack 4 and later you must have the "Increase Quota" privilege (administrator accounts have this privilege by default). CacheSet has been updated to enable this privilege so that it works on SP4.
CacheSet uses a NtQuerySystemInformation call to obtain information about the Caches settings and NtSetSystemInformation to set new sizing information. The working-set information for a process serves as guidelines for NTs Memory Manager regarding how many pages of physical memory should be assigned to the application. Because they are guidelines, conditions can result such that the Memory Manager grows a working-set to a size greater than the maximum, or shrinks it to less than the minimum. However, the settings are factors that will affect the overall allocation, and hence responsiveness, of an application. In the case of CacheSet the application is the file system Cache.
Internally NtSetSystemInformation calls MmAdjustWorkingSetSize, which either grows an applications working set or trims it. If the third parameter passed to MmAdjustWorkingSetSize is 1, the system Caches working set is adjusted, otherwise the adjustment occurs on the current process (the system information calls affect only the system cache). Passing in a minimum and maximum of -1 causes MmAjustWorkingSetSize to perform a working-set clear operation, releasing all pages from the applications working set.