I'd been debating whether or not it made sense to start a thread about my experiment with crypto currency, but since I came back to the forum to discover there's already going on, here's my first update on my less than three week old old experiment with both mining (ZEC) and currency appreciation (BTC + a little ZEC). The numbers will seem quite low compared to folks like Tonyahu, but patterns should hopefully be representative.
Currently running 4 GTX 1060s (purchased for the experiment) and 1 GTX 970 (in the computer I use for VR). Have a 5th 1060 out of commission at the moment, potentially this is just an issue with a bad riser. 1060s are a bit slower than the cards a lot of folks run, but due the demand driving up the cost of 1070 on up, when I pulled the trigger these had the shortest payback time. Currently mining ZEC and getting paid in BTC through NiceHash but I've also experimented with mining ZEC directly through flypool.
I wanted to separate out the idea of "mining crypto currency for profit" from the idea of "owning crypto currency for price appreciation" in my records. "Mining income" assumes I sell everything for dollars at the prevailing price on the day it was earned. "Capital Gains/Losses" tracks the difference between mining income and the actual net worth of the cryptocurrency. I jumpstarted the currency appreciation half of my experiment with ~0.44 bitcoins I found leftover on an old computer. Since if I wasn't doing the experiment I would have cashed that out, I reset my starting value on those coins to the price they would have received on the day I started the experiment.
My sunk costs would be lower if I built a second machine (by $200, or $400 if I subtract out what I spent on the last 1060 that may still come online at some point), but the only way I could have gotten to the point of knowing how to build the second machine was to build the first one. Currently 3 weeks in. Averaging about $13.50/day in mining income and $4.30/day in capital gains. If I can keep that up I'm 58 days from my break even point overall and 84 days away from my break even point considering only income from mining.
The rate at which the difficulty for ZEC mining is increasing has me a little concerned about the likelihood of success for my little experiment. From the start of my experiment to today, difficulty has increased from ~2M to ~3.5M. So far the price of ZEC has increased roughly proportionately ($240/ZEC->$360/ZEC, so I'm not seeing a big decline in my average daily mining take but it looks like the price may be starting to level off.
Anyway, lots of things could go wrong, but it continues to be a fun experiment, the rack I built could easily scale to 24 total graphics cards if I ever decide to put real money into this, and worse case scenario, I've got everything I've spent so far down in my monthly accounts as entertainment/hobby spending, not investment.