Benchmark your SSD or hard disk speed

Jul 11, '12 07:30:00AM

Contributed by: Anonymous

You can benchmark the speed of your SSD or hard disk using a few simple Terminal commands. To test write speed:

time dd if=/dev/zero bs=1024k of=tstfile count=1024
In the output, you should look for something that looks like "bytes transferred in 16.546732 secs (519131791 bytes/sec)." Copy and paste the bytes/sec speed into Google to convert to MB/s (e.g. Google search for "519131791 bytes/s in megabytes/s").

To test read speed:
 dd if=tstfile bs=1024k of=/dev/null count=1024
[kirkmc adds: While we're on the subject, here's an easy way to test data throughput from one disk to another. Open Activity Monitor (in /Applications/Utilities), click on the Disk Activity tab at the bottom of the window, then look at the Data read/sec and Data written/sec numbers. Copy a large file from one disk to another to see how fast it can go. FWIW, my new Thunderbolt drive has throughput of about 100 MB/sec.

You can run the above commands while watching the information in Activity Monitor, and skip making the conversions. This shows that I have a peak read speed of 137 MB/sec, and a peak write speed of 151 MB/sec (an SSD in a Mac mini). The commands above will give you average speeds, whereas Activity Monitor shows the speed in real time, as well as peak speeds. See the comments below for what may be a better approach.]

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