When purchasing a hard drive a savvy consumer needs to look at a number of factors.  Mot people don’t know about any of these factors I am about to explain and will buy whatever is cheapest.  That is nearly always a mistake.

    If you have a 10 year old computer with an older drive; it may be spinning at 5400 RPM (Revolutions Per Minute).  The RPM speed is usually on the label of the drive.  You would have to open the case to find out.  I have never recommended a 5400 RPM drive to anyone as they have become obsolete.  Other speeds are 7,200, 10,000(SCSI) and even 15,000(SCSI) RPM.   Faster RPM’s means as the disk spins; it will be in position sooner for the next read or write operation.

    Transfer rate is the second factor.  This is the speed at which data can be sent from the drive to/from the computer.   This can be ATA 33/66/100/133 (also known as EIDE) or SATA 150/300.   SATA and EIDE are backwards compatible.  Example: you attach an ATA133 drive to an older motherboard that runs only supports ATA66.  The drive would run at 66 vs. the 133 but it would still work.  SCSI systems are very fast but are ususaly found only on network servers.

    External USB-1 drives are quite slow because they are limited to the speed of the USB connection.  USB-2 drives will run much faster than USB-1 but the computer has to support USB-2.  USB-1 is WAY too slow for video.

    MS (milliseconds) is the third factor.  This is how fast the data is located.  Lower is better.  Always stay under 10.

    Lastly, each drive has a data cache.  Again, larger is better.  The data transfer cache is RAM that is part of the hard drive.  If either the computer or the drive gets behind, data is stored in this cache.  It’s a holding area for the slower device.  A cache of 8 meg is common on most drives but the newer mega-drives are using a larger cache.

    Today, the cheaper computers (under $500) may contain a slower hard drive and drive interface.  This allows the manufacturer to knock a few bucks off the price.  It’s always better to get the better PC in the first place because it’s cheaper than upgrading later.  You do get what you pay for!

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