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)