How to format WD15EARS? Which allocation unit size? Please help

Hello, I just purchased a 1.5TB WD15EARS HD and I currently have a raid setup and so I can’t add the drive just yet.

I have it hooked up through a HD enclosure via USB 2.0

I’m formatting it with Vista’s Computer Management utility and I’m not sure which allocation size to choose? Or should I just leave it as default?

I know that these drives are different and use some special WD formatting. I actually thought they use a 4096k allocation size, but I could be wrong.

Should I leave this default, or use a western digital utility or something. Please help.



Just use Vista to partition and format the drive.  It will make sure that it’s aligned.

So just leave it on default?

I’m using WD20EARS, and hope to know the answer.

Currently, I allocated by 64K, but I think 4K is not bad yet.

Have Windows 7 Ultimate 32 bit.

First I formated my new WD15EARS to NTFS with default Allocation unit size. transfer HDD to HDD 50-60.000. from DVD to HDD - 18-20.000 kbps.

All went OK. Under chkdsk it says 4096 .

Under Everest 5.50 it say 512b.


So I did another format, this time I set “Allocation unit size” to 4096.

All went OK.

Same thing under chkdsk (4096) and under EVEREST 5.50 (512b) ?!?!

Transfer rate wenT DOWN!!!  4 TO 1 … HDD to HDD 12-15.000 kbps , and DVD-HDD… under 10.000 kbps…

O man…

Whos wrong…EVEREST or cCHKDSK?!  How to check clusrer size?

Went back to format “Allocation unit size” setting to deafult…transfer rate went UP!!!


Advice / Help??


AFAICT, CHKDSK would be reporting the cluster size whereas Everest would be reporting the sector size.

If you want to see the information that the drive is reporting via the ATA Identify Device command, then run CrystalDiskInfo:

You can capture the Identify Device data block using the Text Copy feature:

If you upload these data, we can determine how your drive is reporting sector size.

You can also view the partition table and NTFS boot sector using a disc editor:

HxD - Freeware Hex Editor and Disk Editor:

If you can show us the contents of sector 0, that will tell us how the disc is partitioned, and whether it is aligned.