A hard drive is a storage place where you install and store all your programs and data. Generally, the bigger the memory capacity, the more data you can store. The memory capacity is usually measured in gigabytes. Currently in the market, you can find hard drive that range from 10GB to as high 500GB.

Disk Storage space
The storage space determines how much data you can store. It is always better to get a hard drive with excess storage space for future use. As a guideline, get a hard drive that is 10-20GB bigger than your current data size.

Drive Interface
The traditional drive interface is using the IDE cable. Its transfer speed range from 33MB/s to 133MB/s, depending on the motherboard and the hard drive bus specification. Ideally, the higher the transfer speed, the better the computer performance. The transfer speed can be identified by the label Ultra DMA33, Ultra DMA66, Ultra DMA100, Ultra DMA133. The number on the label represents the transfer speed in MB/s.

Serial ATA (also known as SATA) is the next generation drive interface. The first version has a maximum transfer speed of 150MB/s and SATA II (second version) delivers 300 MB/s. A version set for year 2008 will deliver 600 MB/s.

SATA has several key advantages over the IDE

1. SATA has a faster transfer speed then IDE;
2. SATA uses very thin and small 7 pins connector that can go up to 1m in length, whereas IDE only allow the flat 40 wire connector that only limit to 46cm. This difference in cable length will affect the heat dispersion inside the casing.
3. SATA has a lower power requirement (250mV) than IDE (5V);
4. SATA technology allows hot-swapping, which means drives can be removed or added while the computer is running. This is not achievable in IDE.


Most of the motherboards come with integrated SATA and IDE interface. For older system, third party SATA controllers can also be placed in any PCI slot, should you purchase a SATA drive.


Hard Drive Revolution Speed
Hard drive revolves at a certain speed. The faster the disk rotates, the more data it can process. 5400rpm used to be the most common speed around. Lately, hard drive manufacturers have started introducing 7200rpm hard drive to the market and the price is comparable to a 5400rpm hard drive.