GPU and ASIC are Bitcoin mining hardware among others, that come with different mining speeds, features and costs.
The Bitcoin mining hardware evolved in four steps.
- First came CPUs (Central Processing Units),
- This was followed by GPUs (Graphic Processing Units) that increased mining speed by 50 to 100 times.
- FPGAs (Field-programmable Gate Arrays) came in 2011 that solely concentrated on Bitcoin mining. They reduced power-consumption and increased speed by making specialised mining farms possible for the first time.
- Finally ASICs (Application specific integrated circuit chips) evolved, that took over the mining industry completely. This was mainly because they were created solely to solve mining blocks. They substantially increased mining speed while extensively reducing power consumption.
Both GPUs and ASICs are highly preferred mining hardware today. In GPU, a graphic card solves complex algorithm whereas in ASIC, a Bitcoin machine solves the complex algorithm, both in order to gain rewards. The basic difference is that while GPUs are fast, ASICs are much faster. But while GPUs are relatively flexible, ASICs are limited to a narrow set of functions. Also, ASICs are comparatively more expensive than GPUs.
This occurs due to technical differenced between both the chips. GPUs have many instruction sets and libraries that allow them to operate on locally stored data. They basically act as accelerators for parallel-working algorithms and are very efficient at performing matrix operations. This not only makes them fast but flexible too. On the other hand, ASIC chips have the whole logic area of chip which is solely dedicated to a narrow set of functions. Due to concise data, they work extremely fast but this conciseness prevents them to operate broadly and limits their function. Also, ASIC chips are expensive to manufacture. They require a team of expensive engineers to be made and need timely technically upgrades.
Despite GPUs comparatively slower speed, they are highly sought after. Financial affordability is a direct factor for it, but indirect financial advantages are also high for them. GPUs have a big market, high resale value and a three-years warranty period. This makes using and reselling them more affordable. Programmers usually buy and use GPUs in the initial years to recover its cost and make profits, and before the guarantee period ends, they resell it. In contrast, ASICs only have a guarantee period of three months and have lower demand. GPUs have high demand due to their multi-purpose tasks. ASICs solely exist for Bitcoin and thus generates less demand and makes reselling difficult.
ASIC’s mining power usage is more than GPU, which makes mining via ASIC costly. ASIC miners are known to be notoriously noisy due to loud sounds produced by its fan. They create too much heat and require a cooling system. So, they are difficult to handle. More importantly, upgrading chips, which is essential to improve mining, is constantly getting difficult. While Graphic cards easily get updated, ASICs require a whole new computer to be upgraded, which is generally not feasible. In the worst case scenario, if the difficulty increases beyond a certain point, the ASICs completely become useless due to their single-dimensional usage.
However, if a person (or organisation) can financially afford ASICs, they generate several benefits from them. Due to their super-fast speed, high profits can be generated in short-run. At large scale usage, profits usually surpass costs, and reselling is not a big issue. In real terms, ASIC miners basically assist large corporations to make money.
However, core creators of Bitcoin and public platforms usually criticise the practice of ASIC usage. ASIC leads to centralisation of Bitcoin shares or monopolisation by large firms, which violates the purpose of a decentralised cryptocurrency. Bitcoin was created with the vision of providing an equal, open and accessible platform to all general users, but the use of ASICs has deviated this goal. This is one of the reasons why Bitcoin is being forked into Bitcoin Gold (BCG).
Forking is simply dividing the cryptocurrency into more entities, and creating its separate digital assets. Creation of BCG is to simply decentralise the Bitcoin market. BCG would be using a different algorithm called Equihash, instead of using SHA-256 which is used by Bitcoin. Equihash is ASIC-resistant but works with GPUs. More about BCG, here.
In conclusion, while ASIC is the fastest and most efficient Bitcoin mining hardware, it is currently losing popularity. Cost and maintenance-difficulty makes GPUs a more attractive option. Moreover, Bitcoin’s new initiative of BCG and decentralisation is further expected to reduce the role of ASIC in the Bitcoin market.