Available KBytes —Amount of physical memory available to processes running on the computer. It is calculated by summing space on the Zeroed, Free, and Stand-by memory lists. Free memory is ready for use. Zeroed memory is memory filled with zeros to prevent later processes from seeing data used by a previous process. Standby memory is memory removed from a working set (its physical memory) of a process enroute to disk, but is still available to be recalled. This counter displays the last observed value only; it is not an average.
Pages/sec—Number of pages read from or written to disk to resolve hard page faults. (Hard page faults occur when a process requires code or data that is not in its working set or elsewhere in physical memory, and must be retrieved from disk). This counter was designed as a primary indicator of the faults that cause system-wide delays. It is the sum of Memory: Pages Input/sec and Memory: Pages Output/sec. It is counted in numbers of pages, so it can be compared to other counts of pages, such as Memory: Page Faults/sec, without conversion. It includes pages retrieved to satisfy faults in the file system cache (usually requested by applications) and in non-cached mapped memory files. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.
Pages Input/sec—Number of pages read from disk to resolve hard page faults. (Hard page faults occur when a process requires code or data that is not in its working set or elsewhere in physical memory, and must be retrieved from disk). This counter was designed as a primary indicator of the faults that cause system-wide delays. It includes pages retrieved to satisfy faults in the file system cache (usually requested by applications) and in non-cached mapped memory files. This counter counts numbers of pages, and can be compared to other counts of pages, such as Memory: Page Faults/sec, without conversion. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.
Pages Output/sec—Number of pages written to disk to free up space in physical memory. Pages are written back to disk only if they are changed in physical memory, so they are likely to hold data, not code. A high rate of pages output might indicate a memory shortage. Windows NT writes more pages back to disk to free up space when physical memory is in short supply. This counter counts numbers of pages, and can be compared to other counts of pages, without conversion. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.
Page Reads/sec—Number of times the disk was read to resolve hard page faults. (Hard page faults occur when a process requires code or data that is not in its working set or elsewhere in physical memory, and must be retrieved from disk). This counter was designed as a primary indicator of the kinds of faults that cause system-wide delays. It includes reads to satisfy faults in the file system cache (usually requested by applications) and in non-cached mapped memory files. This counter counts numbers of read operations, without regard to the numbers of pages retrieved by each operation. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.
Page Writes/sec—Number of times pages were written to disk to free up space in physical memory. Pages are written to disk only if they are changed while in physical memory, so they are likely to hold data, not code. This counter counts write operations, without regard to the number of pages written in each operation. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.
Page Faults/sec—Overall rate at which the faulted pages are handled by the processor. It is measured in numbers of pages faulted per second. A page fault occurs when a process requires code or data that is not in its working set (its space in physical memory). This counter includes both hard faults (those that require disk access) and soft faults (where the faulted page is found elsewhere in physical memory). Most processors can handle large numbers of soft faults without consequence. However, hard faults can cause significant delays. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.
Cache Bytes—Sum of the System Cache Resident Bytes, System Driver Resident Bytes, System Code Resident Bytes, and Pool Paged Resident Bytes counters. This counter displays the last observed value only; it is not an average.
Cache Faults/sec—Number of faults, that occur when a page sought in the file system cache is not found and must be retrieved from elsewhere in memory (a soft fault) or from disk (a hard fault). The file system cache is an area of physical memory that stores recently used pages of data for applications. Cache activity is a reliable indicator of most application I/O operations. This counter counts the number of faults, without regard for the number of pages faulted in each operation.
Pool Nonpaged Bytes—Number of bytes in the nonpaged pool, an area of system memory (physical memory used by the operating system) for objects that cannot be written to disk, but must remain in physical memory as long as they are allocated. Memory: Pool Nonpaged Bytes is calculated differently than Process: Pool Nonpaged Bytes, so it might not equal Process: Pool Nonpaged Bytes: _Total. This counter displays the last observed value only; it is not an average.
Cache Copy Reads/sec—Frequency of reads from pages of the file system cache that involve a memory copy of the data from the cache to the application's buffer.
Cache Copy Read Hits %—Percentage of cache copy read requests that hit the cache, that is, they did not require a disk read to provide access to the page in the cache. A copy read is a file read operation that is satisfied by a memory copy from a page in the cache to the buffer of the application.