SATA2 slow speed issue?

Hi guys,

I feel like copying from one SATA drive to another on my PC is going incredibly slow, it is at average about 80bmps.

Motherboard is GIGABYTE GA-MA790X-DS4 which supports SATA 3TB. The first HDD is a brand new Western Digital black caviar 2TB (6TB speed supported) and the other is 1TB Western digital that supports 3TB speed (both are 7200rpm). CPU is a Phenom 9550 quad core with 3GB of DDR2 1066mhz RAM.

I have checked the bios and the SATA is enabled for AHCI and DMA is enabled in Windows 7.

Surely this should be faster than I am experiencing? USB2 speeds are about this speed as well copying to a memory stick.
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  1. Best answer
    Even on recent SATA II (more properly, SATA 3.0 Gb/s) units, the AVERAGE data throughput is often in the 80 to 100 MB/s range, because that's as fast as a mechanical hard drive can access data. It is limited by the rotational speed of the disks and the speed of moving the heads from track to track. About the fastest I've seen in any lab test is a little over 1.5 Gb/s (roughly 150 MB/s). For the same mechanical reasons, the SATA 6.0 Gb/s HDD's are NOT faster than the previous SATA 3.0 Gb/s units. This does NOT apply to SSD's - they are much faster because they don't have the mechanical limiting factors. Even then, last I looked the SSD's were achieving just over the 3.0 Gb/s rate, and have not reached the limits of the SATA 6.0 Gb/s communications subsystem. That's why that new system was designed for that speed - so it won't be a limit on the latest SSD technology. The speeds never meet the MAX speed spec for the data communication subsystem of 3.0 Gb/s.

    I've never seen USB2 data transfer rates in lab tests that fast. Most ones I've seen are in the 30 to 50 MB/s range for USB2.
  2. NOTE:

    1. speeds on hard drives are about 2x the speed when NOT FULL (outer edge) compared to when nearly full (inner).
    2. A modern 3.5" desktop drive may see up to 120 MBytes/second (60MB/s inner)
    3. An OLDER, 2.5" laptop drive may see up to 40MBytes/second (20MB/s inner)
    4. USB drives are usually limited by the IDE->USB chip not the theoretical 60MB/s USB speed. Typical speeds don't exceed 32MBytes/second

    *5. Due to seek times, smaller files copy SLOWER than larger files. Songs and small picture files can drop speeds as low as 2MBytes/second!!

    There are programs like HDTach or HDDspeed that can benchmark your hard drive.
  3. Best answer selected by nzSkitzo.
  4. Thanks a lot for your responses, at least I know it is normal now and I don't have a fault.
    To be honest the place where I want wrong was thinking the speed of SATA2 was measured in GBps not Gbps, so it makes sense now = ) thanks.
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