Submit Hint Search The Forums LinksStatsPollsHeadlinesRSS
14,000 hints and counting!

Click here to return to the 'Benchmark your SSD or hard disk speed' hint
The following comments are owned by whoever posted them. This site is not responsible for what they say.
Benchmark your SSD or hard disk speed
Authored by: on Jul 11, '12 07:52:12AM

The read speed test is flawed as written. Using /dev/zero as dd's input and output file doesn't hit the disk at all and will return ridiculous speeds like 15-20 GB/sec. The proper way to do the read test is to be to dd the tstfile created by the write benchmark into /dev/null (but only after clearing the RAM cache by using the "purge" command).

This one-liner will test the write speed, clear the cache, properly test the read speed, and then remove tstfile to reclaim disk space:

dd if=/dev/zero bs=1024k of=tstfile count=1024 && purge && dd if=tstfile bs=1024k of=/dev/null count=1024 && rm tstfile

[ Reply to This | # ]
Benchmark your SSD or hard disk speed
Authored by: ericswanson on Jul 11, '12 09:15:21PM

Here's what I get using this method (and dividing by 1048576 to get Mb/sec):

Internal laptop hd (7200 rpm, sata): Write=42.99 Mb/sec, Read=38.09 Mb/sec
External G-Raid (esata): Write=134.76 Mb/sec, Read=192.32 Mb/sec
External Seagate hd (laptop drive, USB-2): Write=33.59 Mb/sec, Read=36.38 Mb/sec
External G-Raid (Firewire 800): Write=60.79 Mb/sec, Read=66.17 Mb/sec
Encrypted sparsebundle image on external G-Raid above (esata): Write=68.66 Mb/sec, Read=81.33 Mb/sec

[ Reply to This | # ]