Quote from: ribuck on July 08, 2011, 03:54:16 PM

A GPU card hashes around 50 times as fast as a CPU. The switch from CPU mining to predominantly-GPU mining occurred during the second half of 2010. So bear in mind that the average miner had around 50 times as many megahashes/second at the end of 2010 than they did in mid-2010.

If you adjust for that, the chart would be fairly level.

The chart uses only difficulty and pricing data. How powerful each miner's machine was doesn't change the chart.

I think what you are saying is that the cost of buying hardware in the begining was much higher in terms of $/MH/S performance because they were only CPUs. So your ROI was closer to the same because it cost around $400/MH/S for CPU power rather than $1/MH/S for GPUs. I can make another chart showing ROI with those considerations in the future.