Slow SATA Transfers


Feb 10, 2009
Hi all,

I have a Vista x64 system with 3 SATA2 drives installed. The system itself has a Gigabyte GA-EX58 Extreme motherboard with SATA2 controllers. All 3 SATA2 drives are connected through my SATA2 controllers on port 1, 3 and 5.

2 of my HDD are Samsung 500GB HD502U Drives
The third is a Western Digital Caviar 1TB WD10EACS

The problem I am having is whenever I transfer anything to of from the WD drive, I get abysmal transfer speeds. They usually start out around 60MB/s and come to rest around 10MB/s. At these rates it takes about 5 hours to transfer 150GB.

Transferring from my other SATA drives is generally pretty fast.

I am on Vista x64 SP1

I have upgraded my chipset drivers to the most recent version, I have verified 'Enable Write Caching on the Disk' is on for all disks. I have made sure all internal cable connections are secure. I have gone through my BIOS but see no settings for SATA other than 'Enable' or 'Disable' There are some RAID settings but I am not on RAID. I can turn on AHCI but when I do that, my computer doesn't boot, saying I have an invalid system disk.

The WD disk that's performing oddly is one that I took out of a WD Passport External Drive because it was being slow in there, as well. Could the drive itself perhaps be failing?

At this point I'm not sure what else to try. Thoughts?