In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce 4 MX 440 are massively better than the Nvidia GeForce 256.

The 4 MX was released over a year more recently than the GeForce 256, and so the 4 MX is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the GeForce 256.

Both GPUs exhibit very poor performance, so rather than upgrading from one to the other you should consider looking at more powerful GPUs. Neither of these will be able to run the latest games in any playable way.

The 4 MX has 96 MB more video memory than the GeForce 256, so is likely to be slightly better at displaying game textures at higher resolutions. This is supported by the fact that the 4 MX also has superior memory performance overall.

The 4 MX has 0.5 GB/sec greater memory bandwidth than the GeForce 256, which means that the memory performance of the 4 MX is marginally better than the GeForce 256.

The GeForce 256 has 4 Shader Processing Units and the GeForce 4 MX 440 has 2. However, the actual shader performance of the GeForce 256 is 0 and the actual shader performance of the 4 MX is 1. The 4 MX having 1 better shader performance and an altogether better performance when taking into account other relevant data means that the 4 MX delivers a marginally smoother and more efficient experience when processing graphical data than the GeForce 256.