Two WD5000AAKS but one is slower than the other


My pc has 3 internal hard drives WDC Blue:

1x WD3200AAJS (OS & Apps) + 2x WD5000AAKS (Storage).

The first of 500GB was bought 2 years ago and the other was bought 2 months ago.

Today I was curious with HD Tune software, it shows that old hard drive is slower than newer hard drive.

In fact, the 320GB’s drive is faster than that 500GB old drive.

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Any idea of why is that?
It will be worthwhile if set up Raid O with these two 500GB drives?
How can I make that drive faster?


that is normal

the newer drive has a newer density in the platters

for example

my wd5000aaks from 2007 has been built with platters of 166 gb each

if i buy another now will be only one platter of 500 gb

do the math… old 3 platters, new one only 1 platter

more information in the same space = more speed reading :slight_smile:

the old drive should Weight more than the new drive…

my drive has the same results that your old drive

but acessing the files is more quick

i will send the print later

If drive A has a data density (bits per square inch) that is four times greater than drive B, then we could expect that A would have twice as many tracks per inch as B, and twice as many bits (or sectors) per track.

The data rate is …

(sectors / track) x (bytes / sector) x (rotations per second)

I expect that your WD5000AAKS-00V1A0 drive would have a single disc with a density of 500GB per platter.

Without knowing anything about your WD5000AAKS-75YGA0 drive, we would expect that its data density would be …

500 x (79.6 / 131.4)^2 = 183GB per platter.

So this would suggest that it has 3 platters.

Similarly for the 320GB drive, its data density is …

500 x (105.9 / 131.4)^2 = 325GB per platter.

So this would make it a single platter model.

BTW, I’m assuming that all drives rotate at the same speed, ie 7200RPM.

here it is the pictures



OK, thanks for explain it   :wink:

one last question:

if I set up a RAID 0 with these 500GB drives (new & old) … how will be the resulting performance?

will be like 2 old drives, like 2 new drive, or something in between?

I mean… it could be better than 320GB drive I’m using now as main dirve or not?

Thanks again.-

i am almost sure that the new drive will be limited by the performance of the older one :confused:

but wait for another response