Create a large file: fsutil file createnew <filename> <length> where <length> is in bytes. The file may be sparse; if it behaves like it is (impossibly fast read times), make a copy with Windows explorer; the copy will not be sparse. Read test: copy largefile nul (nul is a special filename that's roughly equivalent to /dev/null) Watch performance monitor overall disk read speed; the per-process counters take a while to catch up and will show inaccurately low numbers. Write test: cipher /w:c:\ (will write 0x00 bytes as fast as it can to a temporary file)