I’ve read that a newer CPUs can be much faster than an older CPU even if both have the same amount of cores and the same clock speed. It says that newer CPUs can do certain tasks faster. How is that possible with the same architecture?

Question

I’ve read that a newer CPUs can be much faster than an older CPU even if both have the same amount of cores and the same clock speed. It says that newer CPUs can do certain tasks faster. How is that possible with the same architecture?

In: Technology

Answer 1

There are multiple things that can affect the performance of a CPU:

**Number of cycles per instruction** – A CPU executes instructions at a low level. There are for example instructions to add two numbers, or to multiply them. Where an old CPU might for example take two cycles to multiply, a newer CPU might only taken one. This effectively doubles the speed of multiplication without increasing clock speed.

**Speculative execution** – When the CPU executes an instruction, it might need to wait for a component to respond. For example when you read from RAM memory, RAM memory chips have their own speeds.

While older CPUs just waited for the RAM to respond, newer CPUs perform speculative execution of the instructions after the read, where possible. This way it doesn’t have to wait for the RAM, and is thus faster without increasing clock speed.