Mining in the context of cryptocurrency such as Dash refers to the process of searching for solutions to cryptographically difficult problems as a method of securing blocks on the blockchain. The process of mining creates new currency tokens as a reward to the miner. Mining is possible on a range of hardware. Dash implements an algorithm known as X11, which the miner must solve in order to earn rewards.
The simplest and most general hardware available for mining is the general purpose CPU present in every computer. A CPU is designed to be versatile but offers less efficiency than a GPU, which is designed to rapidly calculate millions of vectors in parallel. While specific CPU instruction enhancements related to cryptography such as AES or AVX can provide a decent boost, GPUs offer a significant performance increase due to their multiple pipelines for predictable calculations of the type involved with mining. Finally, ASICs can perform a single operation only. A number of X11 ASICs are now available on the market, which are quickly making CPU and GPU mining uneconomic due to the increased difficulty of hashing arising from the rapidly increasing hash rate. The result is a currency which is more secure against brute force attacks on the Dash blockchain.