I am trying to decide whether I should starting mining XMR by doing a breakeven analysis.
According to this answer, a RX 470 Gigabyte G1 4GB can get 700 H/s. That card is currently $184. If I plug in those numbers (plus the current difficulty, cost of electricity, block reward, XMR/USD exchange rate, etc.) into a profit calculator it claims that I will break even with my video card purchase in approximately 40 days.
That sounds like a very, very short time to recuperate my initial investment! It seems too good to be true. Did I do something wrong? Is mining Monero that profitable?
In addition, the profit model assumes difficulty, the XMR exchange rate, network hash rate, block reward, and average block time are all constants. Obviously, all may change:
- exchange rate fluctuates based on the market dynamics
- hash rate depends on miner participation
- block time can be changed by the devs
- block reward is based on block size (if I understand correctly)
Changes in the first two are open to wild speculation. What about the block time and block reward? Historically, have these changed frequently?