GPUs are much better at mining cryptocurrencies compared to CPUs, although not better than ASICs for this purpose. Well, there are many reasons you might want to mine cryptocurrencies with CPU instead of a GPU such as cost issues because a GPU costs more initially, and uses more power or has a higher power draw than CPU, but it will be much more efficient in the long run and will render more hash power than a CPU and therefore more profitable.
On a normal setting, you would expect a mining rig that comprises of two to multiple CPU or GPU cards combine together to improve effectiveness and outputs. Some aren't profitable alone but will work better when combined but some are, alone.
Whether you use a GPU, CPU or ASIC may depend on the select coin you wanna mine, as much as it would depend on your profitability goals. Some coins do not allow GPU, some allow both GPU and CPU mining. But there is a wide variety in both cases. For instance, some of the coins you can still mine today with CPUs include: Monero, Bitcoin Cash, Dogecoin and ZCash among many others and with GPU, you might consider mining Bitcoin Gold, Aion, Energi, Zencash, Zclassic, ETH, Ethereum Classic, Bitcoin, Monero, Ubiq, Bitcoin Diamond, and many others as well.
With online mining profitability calculators, you can get a glimpse of the amount of profits you would expect when mining a certain crypto that employs a certain mining algo with a certain GPU/CPU/ASIC and hashing algorithm on the fly, although these calculators are far from perfect because profitability has to do with among other indeterminacies like future prices of coins.
And because the GPUs cards cost less and save more power compared to ASICs, GPUs are popular in the cryptocurrency mining arenas.
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Of course, an ASIC card will deliver a very high hash rate for specific coin due to the fact that it is much smaller and lighter for similar performance, and has a higher profit margin compared to GPUs. GPUs are, however, more flexible in their applications compared to ASICs, which are application specific for a given coin.
That said, there are GPU cards specifically made for mining cryptocurrencies and Nvidia and AMD are still the most popular manufacturers of GPUs used for cryptocurrency mining.
If you are assessing performance, the criteria are almost the same when accessing performance.
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You are going to look at power consumption, which will affect performance, noise output, and reliability; hash rates; memory, speed, etc.
Remember to also consider the resale value: if the card can't play games good, then it may mean the resale value will drop significantly if you find it not worthwhile for mining crypto or want to dispose of it later.
A miner's hash rate performance will depend on the type and the version of the miner used as well as the type of VRAM used, and other factors.
Therefore, even if values are quoted in this article, they are far from ideal for later versions of miners, software, and VRAMs. Miner versions and software versions keep coming up. These values are only meant as guidelines.
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