Basic questions on mining

[GardenSandwich]

• Is there a difference between a used card and a new card of the same model? Is it worth it to buy new cards?
• Do hashrates just add up between cards, such has having two of the same card will be twice the hashrate of that one card?
• Is it better to have a cheap GPU with lower profits, or a Expensive GPU that makes more?
• Is the CPU important? Do I need decent CPU or can I get away with an absolute potato?

 

[Tristerin]

1.) No, unless old card has BIOS mods for mining.  Depends on alot, like card, ROI, etc

2.) Theoretically to your exact question - each card is crunching its own numbers however, they dont share or pool resources.

3.) There is so much more involved in this question than what you are asking.  There are fixed costs involved (electricity for example) for most people that you then have to weigh the hash vs electricity consumption.  Is it valuable?  Profitable?  Mining what?  With what?  Where?  All of this is unique to each person mining.  And much more involved then what I just said.

4.) No/Yes - depends.  No not really, in comparison to a GPU.  I can easily think of reasons WHY to have a high core count CPU, but mostly comes from having more people showing up in the hash pool to enhance the coins "popularity" - terrible ROI however.

 

As someone who has a mining rig, the only reason I do is someone smarter than me showed me the numbers, the goals, the reasons, and it all made sense to make that investment.

[RAM555789]

1. As long as there's no major issues with the used card it shouldn't have any problems when compared to a new card. You may wanna consider checking/replacing thermal paste however if its an older card like the GTX 10XX series. 

2.There might be a very small amount of loss but it should just about add up together.

3.Depends on a couple of factors and how long your willing to wait for ROI (return on investment). More expensive GPUs might take a longer ROI but overall should net you a larger gain once you've earned the money back on its card. (78 RTX 3090s mining together in one rig makes this one guy 20k per month). You can look up tools to calculate your hashrate and see how much you can make after electricity costs. For reference those 78 RTX cost about $117,000 assuming they were about at the msrp of $1500 so it would take about 6 months just to get a ROI not including energy costs.

4.CPU is less important as it's not used for mining and you can usually get away with only using a single PCIE lane for mining.

Additional Note: You can also if planning on building a rig for pure mining, flash the cards BIOS to make it more effective for just pure mining.

Legal Disclaimer, I am not a tax expert and am not providing you with legal/tax advice: In 2018 the IRS updated their tax polices to include crypto currencies as part of capital gains tax, meaning you will need to pay tax on your capital gains and provide a 8949 (which is a nightmare because of the amount of transactions you will having from mining) however if you lose money you can take that loss and right it off for future capital gains. Depending on how much mining you do will also depend on if you simply add your income to a 1040 form or if add it into section C which will be subject to more tax but let you write off things like the cost of the GPUs, and electricity used as business expenses.