In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce GT 550M 2GB are significantly better than the AMD Radeon HD 8400.

The GT 550M has a 140 MHz higher core clock speed and 8 more Texture Mapping Units than the Radeon HD 8400. This results in the GT 550M providing 7 GTexel/s better texturing performance. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The GT 550M has a 140 MHz higher core clock speed than the Radeon HD 8400 and the same number of Render Output Units. This results in the GT 550M providing 0.6 GPixel/s better pixeling performance. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The Radeon HD 8400 was released over a year more recently than the GT 550M, and so the Radeon HD 8400 is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the GT 550M.

The GT 550M has 2048 MB video memory, but the Radeon HD 8400 does not have an entry, so the two GPUs cannot be reliably compared in this area.

The Radeon HD 8400 has 128 Shader Processing Units and the GeForce GT 550M 2GB has 96. However, the actual shader performance of the Radeon HD 8400 is 50 and the actual shader performance of the GT 550M is 142. The GT 550M having 92 better shader performance and an altogether better performance when taking into account other relevant data means that the GT 550M delivers a marginally smoother and more efficient experience when processing graphical data than the Radeon HD 8400.

The Radeon HD 8400 transistor size technology is 12 nm (nanometers) smaller than the GT 550M. This means that the Radeon HD 8400 is expected to run slightly cooler and achieve higher clock frequencies than the GT 550M.

The Radeon HD 8400 requires 25 Watts to run and the GeForce GT 550M 2GB requires 35 Watts. The GT 550M requires 10 Watts more than the Radeon HD 8400 to run. The difference is not significant enough for the GT 550M to have a noticeably larger impact on your yearly electricity bills than the Radeon HD 8400.