WD20ears - 4k misalignment and performance hit questions

I have a WD20ears (4k - advanced format drive) installed a couple of years ago and used as storage drive, so never kept much care on performance or speed issues…

But lateley I noticed that something was REALLY wrong with the unit because there were HUGE pauses and slowdowns even clicking on the unit icons and listing for files and directories.

I thought it might be some kind of hardware issue and that the drive was failing, but  WD Diagnostic Utility didn’t detect anything; so I checked for partition alignment and found that 2 partion (on 4) were misaligned.

Yesterday I used the Acronis alignment utility to fix that issue … and now the drive seems to perform as usual, there are no slowdowns or performance hit I can notice anymore.

I have a couple of questions:

  • It is possibile that those HUGE slowdowns I had (there were pauses even at listing files and directories!) could be related to the partition misalignment ? The 2 aligned partitions on the drive were unresponsive and sluggish as **bleep**, too…  and I don’t know if this behaviour can be considered “normal”.

  • checking the SMART status of my units I found this “difference” between this WD20ears and the other WD HD I have on my system on “RAW READ ERROR RATE”

WD20ears : value = 151 - threshold = 51 - worst = 150

All the other drives: value = 200 - threshold = 51 - worst = 200

The question is: are this values normal or something with the unit is going wrong and I should consider for replacement ?

Thanks in advance for replies.

What operating system were you using? 

Mainly Windows 7 Ultimate 64bit… but I may have shared the unit with WinXP, sometimes… I don’t remember exactly (2 years ago I didn’t know too much about AFD and partition alignment)

But here’s another mistery with these 4k AFD units : I have another WD20EARS drive (bought 1 year ago) and I’m sure I used it only with Windows 7 (I never created, formatted or modified partitions with other OS); the unit seems ok (no noticeable slowdowns or sluggishness, performances are quite “normal”) but today I checked the unit with the WD Acronis Alignment Utility 2.0.111 and… SURPRISE!!!.. all 4 partitions on the drive are detected by the software as “not aligned”!!!

As I said before, I’m 100% sure that all the partitions of this unit have been created and formatted inside Windows 7 Ultimate 64bit… so… what happened ???

I’m a bit confused, I don’t understand how (or IF) this “hybrid” drives works…  and WHY these 4 partition are now misaligned even if I never touched them with Windows XP (or another OS)… 

Did you leave the XP jumper on the drive when formatting? That should guarantee the drives are misaligned in Windows 7 since it offsets everyhing by 512 bytes to make it aligned on XP.

The whole 512-byte emulation thing is a horrible kludge to keep the disks compatible with XP, and causes big problems for other operating systems.


I didn’t use any jumper at all, when I bought this second unit I was aware of the “problem” with partition alignment on these “hybrid” drives, so I used my newest WD20EARS exclusively with Win7.

I’m VERY confused… doesn’t seem working too much well this “hybrid”-thingie…