CPU Mining (Central Processing Units)
The CPU is mostly manufactured by Intel & AMD. It is the brains of the computer. While the GPU does the grunt work, the CPU delegates what the components of computer are to do.
When Bitcoin was first created, it was possible to mine as many as 100 coins in one day with only a CPU.
Today, ASIC machines make that impossible.
The cost of electricity may outweigh the reward
If a coin is newer, it is more likely to be profitable with CPU mining. This makes everyone with a computer able to make some coin!
Unfortunately, with high market cap coins, CPU mining may be ineffective because as more machines mine on the network, the difficulty raises higher divvying less rewarded coins to the miners.
What can you mine with a CPU?
Well, there are a few coins that are still profitable to some degree if you’d like to mine with your CPU. Trying several algorithms using a benchmark would help to determine the best fit for your CPU.
Monero uses the Cryptonight algorithm, a memory-bound hashing algorithm that relies on random access to slow memory. It is still often mined with CPUs even though it can be mined with GPUs as well.
Electroneum is another coin that runs on Cryptonight and is quickly gaining world-wide adoption. With a focus on mobile mining, the developers have created a coin that will soon pay for users cell phone bills using ETN (Electroneum).
Alternatively, you could use a service like Nicehash or Honeyminer to get the most out of your CPU and have it all converted to Bitcoin automatically.