UDMA CRC Error Count = cabling problems
Current Pending Sector = active bad sectors that will return I/O error when read
Both are serious errors. The SMART data on your 750GB drive does not look too good!
You should backup anything on that drive right now; and then try to heal it by writing zeroes across its entire surface. The low speeds are caused by XP reverting to PIO mode, this is common behavior though very annoying as it keeps using PIO even after the problem is fixed.
But the most important thing you should do now:
- backup data on 750GB drive
- zero-write 750GB drive
- now check SMART on the 750GB drive, Current Pending Sector data-tab should show ZERO (0) as value; most important damage is now fixed
- format and partition the drive per normal and keep an eye on the SMART data; don't store anything on this drive you don't have backed up or isn't important data; you should treat this 750GB drive as suspect for the rest of its lifetime.
The 320GB drive shows a cabling error; but this could just be from months ago and doesn't have to indicate a problem. UDMA CRC Error Count = Cabling errors; bad power adaptor cables can also cause these issues.
As for the low speed on your 750GB; after you fixed the damage on this HDD using zero-write you can change PIO to DMA mode again by:
- click start, right click My Computer, click Properties
- Click on the button that gives you Device Manager window (second tab)
- Now Device Manager is open; look for IDE/SATA storage controller; not sure how yours is called. Primary IDE controller, Secondary IDE controller, Intel AHCI SATA controller; those things you should DELETE/UNINSTALL with the delete button while selecting it.
- Once you deleted all controllers, reboot Windows XP and upon boot they will be found again and installed; but now it uses DMA mode again
After this procedure, your most annoying problems will be fixed; but please be careful and keep good backups! Your HDDs are showing signs of reduced reliability.
Oh i should add; zero-writing cannot be done with Formatting in XP; as that only reads data not overwrite it. You can download Eraser, which is an open source program for data erasure; but should be able to use it to write random junk across the entire drive. Lot's of other utilities exist that can 'zero-write' your drive.
It does not matter what you write to the drive, as long as all data on the drive is at least overwritten once. This would ensure that all your current pending sectors (bad sectors) will be swapped for reserve sectors, after which that particular problem (bad sectors) is fixed and can no longer cause problems.
You can use Active@ File Recovery to search for lost partitions; but the problem is you will encounter its bad sectors and it will disconnect your disk again; Windows doesn't like disks that don't respond.
You could use Ultimate Boot CD and use one of their utilities to zero-write your drive, but indeed that would cause you to loose data. If you insist on keeping your data, you can use advanced software recovery with Spinrite, which is a commercial product without demo/test version. Both Ultimate Boot CD and Spinrite work outside of Windows.