Measure maximum disk transfer speeds

Disk Benchmark Freeware...

The ATTO Disk Benchmark is a utility provided by Attotech. It is used to measure the maximum speeds at which data can be transferred to and from a disk. The results are calculated by reading and writing blocks of data to a drive and timing how long each operation takes. Various tests are typically run, creating a transfer speed profile that shows both read and write transfer rates in megabytes per second for each user specified data block size. The results are displayed on an easy to read graph. Attotech provide the utility free of charge (available at the below download link).

How to use ATTO to benchmark your own drive

  • Download and the software and run Bench32.exe
  • Select the appropriate drive and click start
  • The tests should start and you will see the graphs updating with speed readings for your chosen drive

ATTO (Bench32.exe) options and features

Direct I/O - use system buffering.
If this option is checked, file I/O on the test drive is performed with no system buffering or caching. Combine this option with Overlapped I/O for maximum asynchronous performance.

Force Write Access - bypass drive write cache.
If this option is checked, file writes to the test drive bypass drive write cache. Otherwise, drive write caching is determined by the drive settings.

I/O Comparison - compare I/O data to detect errors.
If this option is selected, data read from the test file will be compared against the data written on a per block basis. You can select the data pattern for comparison in the Test Pattern dropdown box. You can also run the test continuously by selecting Run Continuously. If any errors are detected, the I/O Comparison Errors dialog box will open upon test completion to display the errors.

Neither - don’t perform overlapped I/O or I/O comparisons.
Select this option if you do not want to perform overlapped I/O or I/O comparisons.

Overlapped I/O - perform queued I/O testing.
Select this option to perform queued I/O. Upon selection, the Queue Depth option appears.

Queue Depth - specifies the number of queue entries for overlapped I/O.
Specifies the number of queue entries for overlapped I/O, i.e. the maximum number of read/write commands that can be executed at one time. This option is only available if Overlapped I/O is selected.

Run Continuously - run the test continuously until errors are detected.
If I/O Comparison is selected, this option appears to allow you to run the test continuously for a specified number of minutes. Testing will be stopped prior to the specified time if any errors are detected.

Test Pattern - specifies the test data pattern.
Specifies the 32-bit data pattern that is written to the data file during testing. This option is available only when I/O Comparison is selected.

Total Length - specifies the test file length.
Specifies the total size of the data file that is created on the test drive. This file is deleted upon completion of testing.

Transfer Size - Specifies the range of transfer sizes.
Specifies the range of transfer (block) sizes used for reading and writing data to the test file. Transfer speeds will be displayed for each size. If the first size is greater than the second size, the test will not be performed for any transfer sizes.


Atto screenshot

Download it and try it for yourself, it's free and easy to use.

Added 11 years ago.


6 years ago.

Useful, informativ and simple

Very good

11 years ago.


11 years ago.

The results are shown as a simple graph which shows IO performance for various file sizes. Pros: Simple to use, free, used everywhere.


4 years ago.



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