Lots of things effect computer performance. We were looking at a few of them in today’s lesson.

Different types of RAM can have a big impact on the performance of a computer system. Why? Data has to be moved in and out of RAM, the quicker this data can be accessed and moved the faster the processor can get to processing it. Cache improves performance, this high speed SRAM is located close (often in) the processor. It allows the contents of RAM to be stored close to the processor, the processor check here for the next instruction, if its not found then it checks RAM. Although this sounds a bit haphazard, cache can improve the performance of the machine quite significantly.

Then we recapped how RAM effects performance.

• More RAM means less need to use virtual RAM, therefor an increase in speed.
• Cache allows for faster access then when the processor gets a cache hits the contents are transferred quicker. there are different types of cache.
• Increases in RAM speed has failed to keep up with the increase in RAM capacity but different RAM has different clock speeds and even different ways of access.

We went on to look at how the speed and type of a peripheral can effect performance and that they require an interface. The interface allows the CPU to talk to the peripheral. (some brief notes below but we will look at this in more detail in a future post)

Functions of an Interface

• Buffering – holding data temporarily while in transit between the CPU and peripheral.
• Data Conversion – changing data into a form the CPU can understand and vice-versa – protocol conversion e.g.
  • serial to parallel
  • voltage conversion
• Handling Status Information – to show whether the device is ready to receive or send data e.g. is the printer ready or out of paper.

A big thank you to Mr. Allen in Airdrie Academy for letting me cut up and publish his revision notes – AA Computer Performance