Higher Computing Computer Systems S. McCrossan 1 Higher Grade Computing Studies 3. Computer Performance Measures of Processor Speed When comparing one computer's performance against another, one of the main criteria is the clock speed of the processor. Another measure that is often used is the number of instructions that the processor executes per second (Mips - millions of instructions per sec). A better measure is Flops (floating point operations per sec). A benchmark test is even better. A benchmark is a standard set of computer tasks designed to allow a computer’s performance to be measured, e.g. sort 300,000 database records.

Higher Computing Computer Systems S. McCrossan 2 Higher Grade Computing Studies 3. Computer Performance Bus Size and System Performance The width of the data bus defines how much data can be accessed in one fetch. Therefore, increasing the size of the data bus will increase the quantity of data that the bus can carry at any one time and so speed up the performance/processing of the computer.

Higher Computing Computer Systems S. McCrossan 3 Higher Grade Computing Studies 3. Computer Performance Data Transfer To and From Peripherals An interface speeds up computer performance. It is used to make the link between the fast processor and a slow peripheral. Parallel data transmission built into a computer will use at least 8 lines to transmit data. Serial data transmission would use one line to transmit data. Parallel data transmission is faster than serial.

Higher Computing Computer Systems S. McCrossan 4 Higher Grade Computing Studies 3. Computer Performance Memory Size and System Performance The main way to improve system performance is to increase the amount of memory that you have in your computer. This means that you can run much larger programs. Most modern systems employ a cache. This is a section of memory between the processor and the main memory. It has very fast access, so sections of a program and associated data are copied there to take advantage of its shorter fetch cycle.