Assembled by someone's own hands mining farms for a long time were the mainstream of the mining industry. Who has not seen a photo with a variety of "batteries" of video cards of the most bizarre kind?
Of course, immediately a lot of companies appeared at the market which offered you already assembled turnkey mining farm. Also, they offer to assemble such farms for you from your components. However, how much do we really need their offers now?
It is necessary to recognize that many users are not able to build and configure the farm on the GPU independently, despite the abundance of detailed instructions published in the network, such as this one. (2. https://www.youtube.com/watch?v=-H1sSrTSDuA 3. https://www.youtube.com/watch?v=QJ-RXajnY7s). At the same time, some "Do-It-Yourself" (DIY) allows you to save a considerable amount.
So, for today the most popular performance of a farm on GPU is 6 video cards NVIDIA GTX 1060 6Gb. The cost of each card is from 300 to 500 USD, depending on your persistence in searching for the cheapest supplier. Other equipment (risers, motherboard, power supply, processor, hard drive, RAM and additional coolers) will cost about 300-400 USD more. The case of the farm can be made from improvised means.
The total cost of the farm, thus, will be from 2000 - 3000 USD. With current exchange rates, the cryptocurrency and the average Russian, Chinese or US electricity tariffs, it will be about 250-270 USD per month. The purchase of a similar assembled mining farm will cost about 3200-3600 USD. Considering the already long payback time of video cards, the increased cost of assembled mining farms makes mining on them economically questionable.
In addition, with the increased complexity of calculations in the networks of the largest cryptocurrencies, the equipment becomes obsolete. The higher the complexity, the less cryptocurrency you can get from the mining farm. However, in some cases (as it was in 2017), the growth rate of the cryptocurrency over and above would compensate the decline in its production.
It is extremely difficult to predict the growth rate of any specific cryptocurrency. It depends on the complexity, since it can jump in a leap depending on the interest to a particular coin and the changes made by the developers in the algorithm. So, for the year 2016, the complexity of the Ethereum production increased by 10 times (from 8 to 80 TH). In 2017 it increased by 24 times (from 80 TH to 1.92 PH). Moreover, the peak value of the extraction complexity of the block exceeded 3 PH.
However, obsolete equipment of the mining farm can be sold in most of the cases. Gamers happily take second-hand video cards for 50-70% of the original price, which allows you to return part of the costs and this serves as a kind of "insurance" against losses.
An additional advantage of a purchased farm can be a guarantee from the seller, but it does not apply to all companies. From many sellers of "turnkey mining farms" it is almost impossible to get warranty maintenance or replacement of equipment.
In addition, many companies save on components (especially they "like" power supplies and risers) and no one guarantees optimal settings. In particular, for many purchased farms it is characterized the excessive consumption of electricity.
Services for assembling and setting up a mining farm from your equipment will be much cheaper. Usually they charge around 5-10% of the cost of components, which makes this solution much more attractive.
Specialized ASICs are not only pay off much faster (at least for today), but also are easier to install and configure than the farms on the GPU.
Complexities arise only when a large number of the miners are combined (more than one controller can support).
At the same time, ASICs become outdated during a maximum of one year. Now the market is the 9th generation of specialized devices (with the fact that the first ASIC appeared in 2012).
However, the creation of a large mining farm from ASIC requires significant investment, so hiring a professional for their configuration and maintenance is quite logical and safer than trying to "figure it out yourself" decision.
In the end, it is worth recalling that newcomers in the crypto industry can think about a simpler form of mining: Proof-of-Stake. This algorithm, which produces many leading cryptocurrencies including OctoinCoin is more energy-efficient and safe. Also, it does not require you to have large computing powers and deep knowledge in the field of video cards and other components of mining farms.