Bitcoin Currency and GPU Mining Performance Comparison
Dollars per Day and your Payoff Period
For our next metrics we have to define a few things. First, in order to find a "dollars per day" we had to set a number as the exchange rate. As of July 11th at 3pm the exchange rate that we found online was $14.30 per Bitcoin. I found that rate at the Mt. Gox website that is a 24/7 exchange for the currency and one that has a daily graph that shows the value as it changes.
Please keep in mind that we understand that these values will change over time not only because of the exchange rate differences but because your ability to mine Bitcoins will slow down over time as the algorithm to find coins becomes more and more complex as the network hashing power increases. Read over the first two pages of the article again to understand WHY this happens but just know the results you will see below are based on an instance in time during this writing process!
To find the daily rate we used the calculator on alloscomp.com that uses the current "difficulty factor" and the Mhash/s rates we found using our benchmarks on the previous page. That factor estimates how long it will take to find the next Bitcoin as of that moment in time - the more coins that are found the more that number will increase, so get in fast! The calculator is able to estimate how much you'll make in USD based on that factor and our input of the exchange rate and Mhash/s for each card.
How did the results pan out for our various graphics cards?
Obviously here the metric will fall in line with the raw Mhash/s rates we found on the previous page but this time we are looking at the performance in actually monetary value. The overclocked ARES card is earning us the most on a daily basis with as much as $7.58 falling into wallet. That is a pretty staggering number considering the HD 5830 will only net us $1.83 per day while the GeForce GTX 460 gets us a meager $0.53! Hard to feed a family on that...
Our next metric is really meant for those hardcore mining gurus that want to invest in GPUs to make money on the system. Based on our estimated prices for each graphics card and the dollar-per-day we can earn with each card, how long does it take a user to pay off the investment in that specific graphics card before you start making that cold hard (virtual) cash?
In this case the lower number is better and indicates your quickest route to profit. You would have to mine on the GTX 285 for 526+ days to pay off the current purchase price of $300 and in fact that increase quite a bit as the ability to mine becomes more difficult over time! (That is obviously the case for ALL of our results.) The quickest payoff comes with the Radeon HD 5830 that takes only 70 days to earn that $129 price tag followed by the HD 5750 and its $115 cost. The ARES card takes as much as 201 days or as little as 145 depending on you overclocking settings both of which are pretty substantial investments.
Finally, just for a fun experiment, I decided to graph the "One year profit" of mining Bitcoins on each of these GPUs (of course baring the changing difficulty of mining we keep bringing up). The formula was simple: take the earned dollars per day of the graphics card, multiply by 365 days and subtract the cost of the graphics card itself. Interesting results here:
Anything you see without a line and number associated with it is a net loss. The GTX 580 as an example would earn $405 over a year but it costs $469 today for a net loss of ~$63. The rest of the cards would earn you something ranging from $1.30 for the GTX 560 Ti up to $1666.70 for the overclocked ASUS ARES!! For an investment of $1100 (when you can find it) and some elbow grease on the overclocking, you could make a pretty penny over the course of a year with this dual-GPU graphical beast!
The Radeon HD 5830 is still the best single GPU card with a $538 return on investment and a 400% profit margin for your $120 upfront. Even the modest AMD A8-3850 would be able to earn its keep with Bitcoin mining earning more than all the profitable NVIDIA GPUs combined.