Three main characteristics affect CPU performance: clock speed, cache size, and number of cores. Each can improve how quickly the CPU processes instructions, but there are limits and trade-offs to consider.
Key points
Definition:Clock Speed: the number of fetch-execute cycles the CPU can perform per second, measured in hertz (Hz). Higher clock speed = more instructions per second = faster performance.
Definition:Cache Size: a larger cache can store more frequently used data closer to the CPU, reducing the need to access slower RAM and improving performance.
Definition:Number of Cores: each core is an independent processing unit. More cores allow the CPU to process multiple instructions simultaneously (in parallel).
Common Mistake:Saying 'more cores always makes it faster'. Not all programs are designed to use multiple cores, so performance may not always improve.
Exam Tip:When asked how a characteristic improves performance, always explain the MECHANISM — e.g. 'a larger cache reduces the number of times the CPU needs to access slower RAM, so instructions are processed faster'.
Exam Tip:You MUST be precise with terminology. 'Clock' alone is NE (not enough). 'Speed' alone is NE. 'Cores' alone is NE. Write 'clock speed', 'cache size', 'number of cores'.
Exam Example:'Computer A has 4 cores and 1GHz. Computer B has 2 cores and 1.4GHz. Why might A be faster for a 3D simulator?' Answer: more cores can process tasks in parallel, even though clock speed is lower.
Increasing clock speed too much can cause overheating, which may damage the CPU or require expensive cooling solutions.