wd5000aars


#1

Hi,

I was about to buy the hdd here

http://www.emag.ro/hard_disk-uri/hdd-western-digital-caviar-green-500gb-64m-sata2–pWD5000AARS

and I just noticed that the rotation speed is not noted. I have looked after WD5000AARS on the wdc site but it gives me no results. Other results on Google show me either 5400 or 7200 rpm. Is there any place where I can find reliable information about the specs of this drive?

Thanks a lot!


#2

This drive is a Caviar Green, part of the Green line of WD.

What dictate the drive speed is the  IntelliPower.

A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and solid performance. Additionally, WD Caviar Green drives consume less current during startup allowing lower peak loads on systems as they are booted.

Basically, this drive runs between 5400 to 7200 RPM, the IntelliPower determines what speed the application that you are running. So, in other words, this drive can run from 5400 to 7200.


#3

According to WD’s deceptive (?) marketing-speak, “for each drive model, WD may use a different, invariable RPM.”

Here is the whole paragraph:

IntelliPower – a fine-tuned balance of spin speed, transfer rate, and caching algorithms designed to deliver both significant power savings and solid performance. For each drive model, WD may use a different, invariable RPM.

This means that each model runs at a fixed speed. It is not variable.

AIUI, a drive’s heads fly on an air bearing generated by the spinning platters. If the rotation speed were to vary, then so would the flying height, leading to variations in read/write amplitude. Therefore the heads are aerodynamically tuned to a particular speed, and that speed is tightly controlled.

The following thread discusses two methods to determine the actual RPM of the drive:
http://groups.google.com/group/comp.sys.ibm.pc.hardware.storage/browse_thread/thread/2a0ee77f6c190f35/0f5a4c36d4afc140#0f5a4c36d4afc140

The simplest method is to measure the width of the access time graph in HD Tune’s read benchmark. The OP’s drive spins at 5400 RPM. Therefore the spread of data points will be about 11 msec, ie the time required for one revolution of the platters.