“It’s done in hardware so it’s cheap” (2012)

For instance, if you want a piece of hardware doing nothing but JPEG decoding, you can bring dispatching costs close to zero by having a single “instruction” – “decode a JPEG image”. Then you have no flexibility – and none of the “overhead” circuitry found in more flexible machines (memory for storing instructions, logic for decoding these instructions, multiplexers choosing the registers that inputs come from based on these instructions, etc.)

Before moving on, let’s look a little closer at why we won here:

This means that, unsurprisingly, there’s a limit to efficiency – the fundamental cost of the operations we need to do, which can’t be cut. When the operations themselves are costly enough – for instance, memory access or floating point operations – then their cost dominates the cost of dispatching.

Source: www.yosefk.com