Comparison based on a single benchmark: graphics score of 3dmark firestrike . Your game / application / benchmark may be having different bottlenecks so comparison may not be accurate for you.

Nevertheless it should give at least some idea about relative performance. There is almost two orders of magnitude difference between the weakest and the most powerful GPU, so even such limited comparison can be still useful.

Firestrike graphics scores can vary significantly based on GPU clocks (sometimes overclocked by user, sometimes due to factory overclocking) and to some degree also thanks to the rest of computer specs (e.g. CPU or memory or GPU drivers). When possible, I tried to find non-overclocked GPU scores or averaged scores from multiple reviews.