Vostro 1500 HDD differences (noisy vs quiet)

I've seen number of people complaining about the noisy HDD. My first Vostro 1500 came with the scratch on the palm rest and a very noisy HDD. I asked for replacement HDD and was told it would be a refurbished one. Dell tech suggested replacing the whole unit. I got my replacement yesterday and willing to share my findings. The replacement PC still has the problem - one dead pixel on the screen. Though this was a relatively easy fix, I swapped it with the old one. The new PC has a dead silent HDD. I ran some tests with HDTune app and found a huge difference in performance. I will post the pictures once I get home.
Both HDD were switch to AHCI mode since they seem to perform faster with less CPU usage according to HDTune reports. Neither of the HDDs have performed as purely as the one in this review http://www.notebookreview.com/default.asp?newsID=3918&review=Dell+Vostro+1500
Both HDD showed up as ITEM NUMBER 341-4885 in the order. The noisy one happens to be made by Hitachi and the quiete one is made by Fuji.
I will do Nero CD/DVD speed test and keep the one that performs better if there is a substantial difference.

It would be interesting to see other people posting screenshots of HDTune results.

 

My HD Tune with the 160gb Seagate.

 

measurements from the first 1500 I received.
HDD

CD/DVD-drive


from the second vostro 1500
HDD
http://img514.imageshack.us/my.php?image=hdtune4yy9.png
CD/DVD-drive
http://img514.imageshack.us/my.php?image=cddvd2hw2.png

 

Does it decrease performance though by changing it into "quite" mode?

 

I haven't tried swithing. I do know for the fact that quite mode was enabled in BIOS of my first Vostro 1500.

Here is an interesting thread that may help those with HDD noise issue.
http://forum.notebookreview.com/showthread.php?t=168425