Cache Faults/sec is the rate at which faults occur when a page sought in the file system cache is not found and must be retrieved ...

Cache Faults/sec is the rate at which faults 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 shows the number of faults, without regard for the number of pages faulted in each operation.