A451 – Primary and Secondary Storage

Computer’s have many types of storage, however this post will look at:

  • What is primary storage
  • What is secondary storage
  • How processor’s effect memory
  • SSD Vs HDD

What is Primary Storage?

Primary storage is the main memory (Cache, RAM) where the operating system is. Primary storage is temporary and is smaller but more expensive than secondary storage, it’s all faster than secondary storage.

ram chip 2RAM

What is Secondary Storage?

Secondary memory can be external devices like Hard Drives, SSDs, USB Sticks, etc. Secondary storage is also external memory storage.

Accessing secondary storage takes 1000x longer than accessing primary storage, and even though there’s more memory, it costs less money.

Laptop-hard-drive-exposedHard Drive

How processors effect memory (i3, i5, i7).

Core i3 chips have 3 or 4MB of cache, while i5s have 6MB and the Core i7s have 8MB.

The more cache a PC has, the faster it will run and the better it is.

intel-processorsIntel Processors


SSD stands for Solid State Drive and HDD stands for Hard Disk Drive.

There are no moving parts to an SSD, instead, information is stored in microchips. However a HDD uses a mechanical arm with a read/write head to move around and read information from the right location on a storage platter. This is what makes SSD so much faster.

SSD’s have less power draw, averages 2–3 watts, resulting in 30+ minute battery boost while HDD’s have more power draw, averages 6–7 watts and therefore uses more battery. SSD’s are expensive and cost around $0.10 per gigabyte while HDD’s only cost around $0.06 per gigabyte. Using an SSD an operating system will take around 10-13 seconds to boot up, while a HDD will make it take around 30-40 seconds to boot up.

So, put simply, SSD uses less power, runs faster however costs more money. HDD uses more power, runs slower and costs less.


Now we’re going to compare the Intel SSD 320 Series 40GB 9.5mm 2.5 inch SATA2 Solid State Drive” and the Generic 40GB 40 GB 2.5 Inch IDE(40 gb 2.5″ PATA) Laptop Hard Drive 4200 RPM, both products are from amazon.co.uk

First of all the price of the SDD card is £46.74 while the HDD is considerably cheaper at £15.

The SDD card has been claimed to have a “random read performance up to 39,500 input/output operations per second (IOPS)1 and sequential read performance of up to 270 megabytes per second (MB/s)” as quoted by Intel.

The HDD is claimed to run at “4200 RPM” which stands for Revolutions per Minute, which is how many times the disc in the hard drive spins per minute. The higher the RPM, the faster the data will be accessed.






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