Understanding a model no. would help you know about features of it by simply checking it label & you would no longer have to be dependent on not-so-informed salesman in your local shop. many times there are different model no. of exact same capacity but they differ in cache size which has a direct result on performance. more cache means faster performance

Now we will try to understand model number of various hard drives from different manufacturers.

Note: i would discuss only about consumer series internal hard drives from popular manufacturers. discussing others are beyond the scope of this guide.

Where do i find model no?
Its written clearly on faceplate of hard drive with bold characters along the serial no and other information like date of manufacturing etc.

1)Seagate

sample model number:ST3500630AS
we break is as: ST-3-500-6-30-AS

• ST: Company initials. ST= “Seagate Technology”, STM – Seagate Technology Maxtor(Maxtor Hard drive).
• 3: Form factor. 3 = Standard 3.5″ inch drives; 9 = 2.5″ inch Laptop drive.
• 500: Total Capacity in Gigabytes(1000mb = 1GB). this is a 500GB model.
• 6:Cache Size. 0 = 2MB, 2 = 2MB, 3 = 8MB,4 = 16MB, 6 = 16MB and 8 = 8MB. Note:the cache is the buffer memory between the controller and the mechanical hdd. the more cache it has – the more data it can store to transmit off to the controller. the faster data access on the hdd will be.please don’t confuse it with CPU Cache.
• AS: Connector Interface type, A= 40pin PATA or IDE and AS=SATA interface.

Link:How to interpret Seagate model numbers

2) Western Digital

sample model number::WD6400AAKS
we break it as: WD-640-0-A-A-K-S

WD:Company initials

640: drive capacity in Gigabytes. its a 640GB drive

A:Form factor.

A:Brand/Series

K:RPM/Buffer Size or Attribute
S:Interface Type

Link: Model Number Format for WD Products