Old good CacheSet utility by Mark Russinovich. New information about system cache was inroduced under w2k. I have added displaying of this information.

Sources:

Under NT4 and previous NT versions NtQuerySystemInformation() function for

#define SYSTEMCACHEINFORMATION 0x15

query filled the following structure:

typedef struct {
	ULONG    	CurrentSize;
	ULONG    	PeakSize;
	ULONG    	PageFaultCount;
	ULONG    	MinimumWorkingSet;
	ULONG    	MaximumWorkingSet;
	ULONG    	Unused[4];
} SYSTEM_CACHE_INFORMATION, *PSYSTEM_CACHE_INFORMATION;

Since w2k Windows internal definition of SYSTEM_CACHE_INFORMATION changed, but was not documented prior to WinXP.

typedef struct {
	ULONG    	CurrentSize;
	ULONG    	PeakSize;
	ULONG    	PageFaultCount;
	ULONG    	MinimumWorkingSet;
	ULONG    	MaximumWorkingSet;
	ULONG    	TransitionSharedPages;
	ULONG    	PeakTransitionSharedPages;
	ULONG    	Unused[2];
} SYSTEM_CACHE_INFORMATION, *PSYSTEM_CACHE_INFORMATION;

Together with SYSTEM_CACHE_INFORMATION structure MS changed behaviour of System Cache in Task Manager. Under NT4 this was only File Cache size (CurrentSize and PeakSize members). Under w2k System Cache shows summ of File Cache and memory size, consumed by loaded libraries. Note, after process termination this memory is not freed immediately. Thus, we can observe instant growth of System Cache and noticeble delay on shutdown, even with Fast Reboot.