To create this graph we took all performance results of all benchmarks and all resolutions, threw them together and calculated the relative performance of each card, compared to our review sample.
This graph was created by taking the relative performance numbers and putting them in contrast to the average power consumption results. To offset power consumption of the rest of the system we subtracted 50W from the average consumption.
If you are looking for the best bang for the buck, then you will love this graph. We looked up the current USD price of each card on the online shop Newegg and used it and the relative performance numbers to calculate the Performance per Dollar Index. Please note that this is not an exact science, prices can vary and you may be able to get a great deal on Ebay, for example. Also some cards are not available on the general market anymore, so their prices typically tend to be higher than the current ones.