SATA Drive is very slow

[SuperStruct]

I have 2 hard drives that are the same exact brand and size (Seagate SATA 250GB ). One of them is being VERY slow. I ran HD Tach on both drives and I received the following results:


---Normal Drive---
Random Acces: 15.6ms
CPU Utilization: 4%
Average Read: 56.1 MB/s


---Slow drive---
Random Acces: 15.2ms
CPU Utilization: 100%
Average Read: 3.7 MB/s



When I am transferring files to/from this drive, my computer slows down almost to the point of being completely frozen (I can't even see the mouse because the CPU is being used from the drive I/O!)

Here's my question: Is this a problem with the hard drive, the serial cable, or the motherboard? How can I troubleshoot this problem?

 

[Codesmith]

Check to see what DMA transfer mode is being used. It could be using PIO mode which is very slow.

You can manaully lower the speed, but excessive comunication errors will also automatically downgrade a device.

My external SATA enclosure uses an extra long SATA cable and often it gets kicked down to PIO mode.

Swap ports and cables with the fast drive, then run a full diagnostic on the drive. Use Seagates Online Tools. Also check the smart status.

Obviously if the test indicate problems you RMA the drive.

If the drive is slow but passes the test, you should talk to Seagates technical support before RMA's the drive.

Always fully test all new drives. Never assume they work. You never know how many times the box was dropped before reaching your door or the store shelf.