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Friday, February 15, 2008

Test the transfer rate of storage devices

Hd Tach
Support for Windows 2000 and Windows XP only
HD Tach is a low level hardware benchmark for random access read/write storage devices such as hard drives, removable drives (ZIP/JAZZ), flash devices, and RAID arrays. HD Tach uses custom device drivers and other low level Windows interfaces to bypass as many layers of software as possible and get as close to the physical performance of the device possible.

New versions of our benchmarks will continue to allow free non-commercial use, however, as before advanced features will only be available in a registered or commercial version.

The trial version of HD Tach measures the sequential read speed (at various points on the device), the random access speed, interface burst speed and CPU utilization of the drive. The registered version adds sequential write testing.

Download Trial Version HDTach-3-0-4-0 Updated at 7:33 AM 15-Feb-08

Online forums for comments on the current HD Tach and desired features in a future HD Tach is available here.

HD Tach Publisher's description

HD Tach is a physical performance hard drive test which utilizes a special kernel mode VXD in order to get maximum accuracy by bypassing the file system. A similar mechanism is used in Windows NT/2000.

The HD Tach sequential read test is a little bit different from other benchmarks. Most benchmarks create a file on the hard drive and test within that file.

The problem is that modern hard drives use a zone bit recording technique that allows different read speeds depending on where the data is located. Data on the outside of the drive is much faster than data recorded on the inside.

HD Tach reads from areas all over the hard drive and reports an average speed. It also logs the read speeds to a text file that you can load into a spreadsheet and graph to visually read the results of the test.

In addition to sequential read, HD Tach tests the drive's random access time. Random access is the true measure of seek speed. Many drives advertise sub 10 millisecond seek speeds, but seek speeds are misleading.

Finally, HD Tach tests the drive burst speed. The burst speed is the speed that data can be accessed from the drive's on-board read-ahead memory. This measures the speed of the drive and controller interface.

The non-commercial version of HD Tach gives you access to all the functionality, ease of use and reliable benchmarking you expect from HD Tach. In addtion, we have added the ability to save benchmark results and graph your saved benchmark results against previous results or results from the new, included, drive database.(HD Tach 2.70 adds Windows NT, 2000 and XP read testing in the trial version! In the past, support for these operating systems was only available in a registered copy. The release of HD Tach 2.70 is just the beginning of new things, however, as we have started a complete rewrite of our benchmark products.

We have created this database from benchmark results sent in by our users through the new 'Upload' feature of HD Tach - after running the test you are given the option to send your drive benchmarks in to Simpli Software for inclusion in our database.


Before benchmarking, reboot your computer. This will clear system caches and unload many unneccesary programs. Upon booting quit all programs that may have been

loaded during the boot process, task bar icons, disable virus scanners. Advanced users should unplug the network cable and disable the swap file.

Give your system time to ‘stabilize’ - Windows does a lot of work in the background, so do not use HD Tach until you see your hard drive light stop blinking for 10-15

seconds. This may take one to two minutes after boot. During the benchmark do not move the mouse or press any keys.


HD Tach will display a list of drives in the system. Select a drive and click the 'Run Test' button to benchmark. You may also select between 'Quick read' or 'Long read'.

'Long read' should produce more accurate read speed benchmarks, but will take 5-6 times longer than the 'Quick read'.

More details about the benchmarks are available in the tests.rtf file. A brief description and parameters used for HD Tach Consumer follows.

Access time (in milliseconds) - time to read one random sector from the hard drive. Includes seek time, latency, and read one sector. 512 random accesses are performed,

average value reported.

Burst speed (in megabytes per second) - maximum speed of the computer to hard drive interface. This represents the speed of data transferred from the hard drive on-board

-cache to the system memory. Burst speed can be used to determine if the drive is running at the higher speeds offered by ATA133, SCSI, etc. The burst speed uses a

maximum of 128KiB block size, minimum of 32KiB block size, a single 128KiB pre-read and 32 repetitions.

Read speed per zone (in megabytes per second) - Each zone is displayed on the onscreen graph. Generally hard drives are faster on the outside of the disc (sector 0) and

slower at the inside (end of disc) - your graph should reflect this. A 64KiB block size is used. The Quick read tests a maximum of 64 zones, with a 4MB preread area and a

4MB test area. The Long read tests a maximum of 256 zones with a 16MB preread area and a 16MB test area. The long test may take up to 8 times longer to execute.

Average read speed is reported per zone.

CPU utilization (as a percentage) - This reflects the amount of time the CPU needed to read data from the hard drive. Generally a good drive interface will use less than

10%. The system is tested at idle (no hard drive usage) for 5 seconds to get a base CPU utilization. During the next 5 seconds the drive is sequentially read with a 64KiB

block size while CPU usage is monitored. The difference between idle CPU and loaded CPU is reported.


HD Tach RW offers two options in addition to the above.

The enable write test check box will be active when you have selected a removable media device (such as a flash disk) or a secondary, non-partitioned, hard drive. This will

enable the sequential write test for the device.

The Full Bench option also becomes available as an alternative to quick or long bench. The full bench will benchmark every sector of the hard drive instead of picking small

zones on the drive like quick or full. A full bench could take one to two hours on a 120 gigabyte hard drive. Full bench uses varying zone sizes for different device sizes to

minimize the number of zones benchmarked. Under 1GB, 8MB zones are used. Under 40GB 64MB zones are used, under 100GB 128MB zones are used and for all other

disk sizes 512MB zones are used.


HD Tach (Free): The non-commercial version of HD Tach is to be used only for non-commercial purposes or for a limited evaulation by commercial customers. Other

versions, listed below, are available on our web site for a nominal cost.

HD Tach Commercial License: The purchase of an HD Tach commercial license entitles the purchaser to use HD Tach on up to one computer at a time for commercial use.

HD Tach RW: HD Tach RW adds several features. Sequential write test is available on removable media and non-partitioned fixed disks. Additionally, when an RW user

chooses to save a set of benchmark results a .csv (comma separated values) file is saved for use in spreadsheet programs or internal databases. Finally, HD Tach RW is

capable of performing the sequential read and write tests on the entire disk instead of the small number of zones in the quick and long test.

HD Tach OEM: HD Tach OEM is not yet available, but will be an advanced interface to the Tach benchmark library allowing control over all test parameters, including

running the same test with different parameters (example: sequential read with 32KiB blocks and 64KiB blocks). Users will be able to create test sets to perform on

selected devices and use the CSV feature to chart results in any form imaginable.

FAQ for flash drive
Is 16 mb per second consider fast or slow or what for an 8 gb flash drive?
What are 2.0 USB speeds?
16mb/sec read speed is considered to be quite fast (fastest one on the market can do 20-24mb/sec) and 16mb/sec write is very fast.

USB2.0 high speed:
Theoretical rate: 480Mbits/sec = 60MB/sec
Practical rate: 30-40MB/sec

See also USB 3.0 SuperSpeed

Hd Tach v3 0 1 0 including sequential write testing

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