In terms of overall gaming performance, the graphical capabilities of the AMD Radeon HD 7770 MSI PMD1 Edition are significantly better than the AMD Radeon R7 250 v2 2GB.
The HD 7770 and the R7 250 have the same core clock speed of 1000 MHz, but the HD 7770 has 16 more Texture Mapping Units than the R7 250. As a result, the HD 7770 exhibits a 16 GTexel/s better Texture Fill Rate than the R7 250. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.
The HD 7770 and the R7 250 have the same core clock speed of 1000 MHz, but the HD 7770 has 8 more Render Output Units than the R7 250. As a result, the HD 7770 exhibits a 8 GPixel/s better Pixel Fill Rate than the R7 250. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.
The R7 250 was released less than a year after the HD 7770, and so they are likely to have similar driver support for optimizing performance when running the latest games.
The R7 250 has 1024 MB more video memory than the HD 7770, so is likely to be much better at displaying game textures at higher resolutions. However, overall, the HD 7770 has superior memory performance.
The HD 7770 has 43.2 GB/sec greater memory bandwidth than the R7 250, which means that the memory performance of the HD 7770 is noticeably better than the R7 250.
The Radeon HD 7770 MSI PMD1 Edition has 640 Shader Processing Units and the Radeon R7 250 v2 2GB has 384. However, the actual shader performance of the HD 7770 is 544 and the actual shader performance of the R7 250 is 343. The HD 7770 having 201 better shader performance and an altogether better performance when taking into account other relevant data means that the HD 7770 delivers a significantly smoother and more efficient experience when processing graphical data than the R7 250.
The Radeon HD 7770 MSI PMD1 Edition requires 150 Watts to run and the Radeon R7 250 v2 2GB requires 65 Watts. We would recommend a PSU with at least 500 Watts for the HD 7770 and a PSU with at least 400 Watts for the R7 250. The HD 7770 requires 85 Watts more than the R7 250 to run. The difference is significant enough that the HD 7770 may have an adverse affect on your yearly electricity bills in comparison to the R7 250.