Is there a limit to computing power?
There are several theoretical limits to computing speed such as:
The speed of light: As far as modern physics can determine information can not propagate faster than the velocity of light. This causes a certain time delay with every computational step.
The amount of time for each step: The theoretical smallest increment of time is a Planck unit which means there is an upper limit to cycles per second.
Landauer's principle: The lowest possible theoretical amount of energy consumed by a computational operation. Circuits can be damaged by excessive heat and energy used creates heat so the less energy consumed by each computer operation the more computing operations that can be performed.