What affects Performance?

What affects Performance?

1. Cores

   • Where instructions are read and executed
   • Processors can have multi-cores
     • Dual Core Quad Core 8 Core
     • The amount of cores multiplies the number of instructions which can be executed
       • e.g. 2GHz Single Core Processor executes 2 Billion Instructions 2GHz Quad Core Processor executes 8 Billion Instructions 2x4 = 8

2. Clock Speed

   • How fast the computer is
   • Measured in Hertz
     • 1GHz Processor executes 1 Billion Instructions per second
       • 2GHz = 2 Billion 4GHz = 4 Billion etc.
     • Number of Cycles per second

3. Cache Size

   • Very Fast but Very Small from 8KB to 64KB
   • Acts as a intermediary between the processor and RAM
   • Used to temporarily hold instructions and data that the CPU is likely to use again.
   • Has 3 Levels
     • L1 - Usually part of the CPU already and is the smallest and the fastest cache to be accessed
       • L2 & L3 - Extra Caches which can be built between the CPU and the RAM. The more L2 and L3 memory available, the faster a computer can run. However, L2 and L3 cache takes slightly longer to access than L1