In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce 8800M GTX SLI are noticeably better than the Nvidia GeForce GT 550M 2GB.

The GT 550M was released over three years more recently than the 8800M GTX, and so the GT 550M is likely to have far better driver support, meaning it will be much more optimized and ultimately superior to the 8800M GTX when running the latest games.

The GeForce 8800M GTX SLI and the GeForce GT 550M 2GB have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The 8800M GTX has 176 GB/sec greater memory bandwidth than the GT 550M, which means that the memory performance of the 8800M GTX is massively better than the GT 550M.

The GeForce 8800M GTX SLI has 192 Shader Processing Units and the GeForce GT 550M 2GB has 96. However, the actual shader performance of the 8800M GTX is 96 and the actual shader performance of the GT 550M is 142. The GT 550M having 46 better shader performance is not particularly notable, as altogether the 8800M GTX performs better when taking into account other relevant data.

The GT 550M transistor size technology is 25 nm (nanometers) smaller than the 8800M GTX. This means that the GT 550M is expected to run slightly cooler and achieve higher clock frequencies than the 8800M GTX.

The GeForce 8800M GTX SLI requires 130 Watts to run and the GeForce GT 550M 2GB requires 35 Watts. The 8800M GTX requires 95 Watts more than the GT 550M to run. The difference is significant enough that the 8800M GTX may have an adverse affect on your yearly electricity bills in comparison to the GT 550M.