Well...after 4-months mining (during the Summer) with some Video-card-rigs. I have to tell that all this hardware is worn-out to a level it cannot be resold anymore (Video-card Fans are all broken, and Power-units have burned cables and plugs... these things aren't made for 1200Watt, 24/7 duty).
are you overclocking by increasing the voltage? gotta becareful.. i have mined with my 6870s for more than 2 years and none have any issues, just resold all recently at 60%+ cost basis, actually 75% if you count the included free game coupon that came with the card that i sold back then. And have upgraded to r9 270-280 You need good cooling to make sure the chip is at low temp and fan isnt going at full speed all the time, mine is kept <70C at full load and about70% fan rpm. Also dont buy the most highend high power video cards those are way expensive, loses more value on resale, and generate tons of heat. Get the mid tier version which run much cooler, the r9 270 is my favorite it runs 100% stable and cool. Also get one of those, run it on max and blow it directly at the intake of the video cards, it does wonders. http://www.amazon.com/Stanley-65570...466328&sr=8-1-fkmr0&keywords=stanley+blow+fan
Yes.. I know all of this (after learning it the hard way...which will be the same for every newbie jumping into script-mining). I have Sapphire 7950 cards and ran them till 90C, but had to replace all Fans (with high speed professional Delta's). Now they run very well, but cannot resell them anymore (no problem, they already made a huge profit). But I still have huge problems with 1200/1500W Silverstone Power Units. That was really a bad buy. Their low quality cable-plugs just melt... their dumb designers selected a 8 pins plug for 25A feed (only 3 pins for the +12V, just melt and burn). Lessons learned: buy Seasonic, Enermax or Lepa instead: they have 12 pin plugs (with 6 pins for +12V).
Yes, they forgot to mention the investment cost. You tried to interpolate it, but we don't know if their equipment has the same ROI than small miner's. The video did mention the hardest problem, when to cash out. With so many coins created, the difference can be quite big both up and down... It is amazing how much energy is wasted on this thing. I calculated the current cost of a newly minted coin to be around $50.