[Solved] HDD keeps switching back to PIO mode

Hi everyone,

I'm running a 500GB Seagate Barracuda 7200.12 SATA HDD (for OS and various software) that keeps switching back to PIO mode. I've tried the following methods (in no particular order) but it still reverts back to PIO mode after a few boot-ups.

1. Replace SATA cable with the one that I'm using for my 1TB (1TB works flawlessly)
2. Uninstall/reinstall IDE channel repeatedly
3. Reformat and reload Windows XP
4. Plugged in the HDD to different SATA ports on my motherboard

I've tried Microsoft "Fix it" software that claims to help solve the problem, but it still persists.

My PC specs are:
MOBO + CPU: MSI P43 Neo3 + Intel E7400 2.8gGHz
RAM: 2 x 2GB Kingston DDR2
PSU: Andyson G530
GPU: Radeon HD 4850

Below are a few screenshots of HD Tune diagnostics:

Benchmark of 500GB running in PIO mode

1TB running in Ultra DMA 5

Health of 500GB in PIO mode

Is this a symptom that my HDD is failing soon? Or is it a motherboard issue? Any solutions that might help solve it?

6 answers Last reply
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  1. This is a known bug with XP, where drives just randomly seem to get set to PIO mode. However, the HD Tune image at the bottom is a bit troubling, so I'd be sure to hit the manufacturer's site and get their diagnostic program. You may well have caught the drive in the very early stages of failure. If you don't have a backup of anything important on that drive, now would be as good a time as any to make sure you do. Even if it turns out it's just the XP DMA bug and nothing else, you generally can't go wrong having a backup of important data.
  2. You also have a current pending sector count of 9. I'm surprised this isn't flagged also. It looks as if the drive is on it's way out. You may want to make a backup soon, just in case.
  3. Windows XP will switch from DMA mode to PIO mode if it encounters 6 CRC errors.

    There are some solutions and workarounds here:

    The following article explains how to edit your registry so that 6 consecutive CRC errors rather than 6 cumulative CRC errors are required to trigger a switch to PIO mode:

    IDE ATA and ATAPI disks use PIO mode after multiple time-out or CRC errors occur:

    It involves adding a "ResetErrorCountersOnSuccess" entry.

    Your SMART attributes are explained in the following article:

    HD Tune is not the best SMART tool, so I would ignore its warnings and interpret them for myself. For example attributes 0A and B8 are perfectly OK (normalised value = 100, raw value = 0). I believe HD Tune's warning is triggered because the Current and Threshold values are "too close".

    Attribute B7 is telling us that there have been 124 SATA Downshift Error Counts, so this would suggest an interface problem. However, the UDMA CRC Error Count is zero, so this seems inconsistent (?).

    Attribute BB is indicating 415 Reported Uncorrectable Errors, and there are 8 Reallocated Sectors and 9 Pending Sectors (as already mentioned), so I expect that these may be causing the PIO problem.

    Attribute BC appears to be reporting 10 (= 0x000A) Command Timeouts.

  4. Thanks guys for the replies.

    cl-scott: I've downloaded Seagate Sea Tools (or something along those) lines but it throws up a windows error whenever I try to run it. I've nothing much except my OS in the 500GB so if the worse case scenario happens, I won't really lose that much data.

    Hawkeye22: noted with thanks! :)

    fzabkar: I've already used Windows "Fix it" software from the second link you posted. I've just reinstalled the driver and it's running in UDMA 5 for now. Let's hope it stays this way.

    Anyone else thinks it's a HDD problem? If it is, I'll probably get a new SSD. I just don't want to do so then realise it's a motherboard problem :(
  5. SeaTools for Windows sometimes has problems with certain SATA controllers or drivers. Instead you could try running SeaTools for DOS from a bootable CD.

    In any case, it's definitely a drive problem.
  6. Thanks for all the replies!

    I guess it's time to get a SSD then.

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