Although an ASIC can be built to provide optimal hashrates on an algorithm, the Graphics Processing Unit (GPU) is much more powerful than the CPU, and more flexible than an ASIC in their application. The GPU is the chip that enables graphics cards (often called GPUs for brevity in mining circles) to perform millions of repetitive calculations at the same time so that games can be rendered in real time. They are also used to render special effects, or for machine learning and artificial intelligence. Whereas an ASIC is purpose made to mine a single algorithm, a GPU is capable of mining different algorithms. It’s possible you could mine Ethereum, Monero, Zcash, Grin and many other coins with the same GPU.