How to: Linux check IDE / SATA hard disk transfer speed
So how do you find out how fast is your hard disk under Linux? Is it running at SATA I (150 MB/s) or SATA II (300 MB/s) speed w/o opening computer case or chassis?
You can use hdparm command. It provides a command line interface to various hard disk ioctls supported by the stock Linux ATA/IDE/SATA device driver subsystem. Some options may work correctly only with the latest kernels (make sure you have cutting edge kernel installed). I also recommend to compile hdparm with the include files from the latest kernel source code. It provides more accurate result.