Something happened to my less than a year old HDD. It was running fine until now.
My other drives have speeds from 57 to 70 MB/s - benchmarking in HDTune. The slow drive really kills the loading times of various games (from a few seconds to a few minutes, and from a minute to about 5 minutes).
I tried rebooting, didn't help. I tried to shutdown PC, disconnect drives power and data cables, and plug them again in - still didn't work.
This happened to my PATA drive once - but it just switched to PIO mode, nothing serious. I know that this can't happen to SATA drive, but it might switched to SATA I, right? But still the speeds wouldn't be as low as they are.
Next time please mention what operating system you are using.
This sounds like a PIO issue; please use HDTune to identify the PIO issue. Run the standard benchmark. If it shows a horizontal line of no more than 16.6MB/s and has very high CPU utilization, then you are likely running in PIO mode.
Usually, this is remedied by going to the device manager and deleting/uninstalling the primary/secondary IDE controller. Or in your case the SATA controller.
Please note that this issue may be caused by cabling errors; if the above trick doesn't work post the drive's SMART info here. If the number of "UDMA error count" is higher than zero, you have cabling issues.