The NVIDIA GeForce RTX 5090D is the objective winner of this comparison, securing victory in ten out of thirteen measured categories. Its most significant technical advantage is the shader unit count, which is 963% higher than that of the AMD RX 6600 XT. This massive disparity in core hardware highlights the substantial architectural superiority of the NVIDIA GeForce RTX 5090D across the majority of the evaluated specifications.

Users prioritizing raw hardware power and the highest available shader capacity should choose the NVIDIA GeForce RTX 5090D for their system. Conversely, the AMD RX 6600 XT is the logical selection for budget-conscious buyers, as it offers an MSRP that is 84% better than the alternative. Selecting between these two components depends entirely on whether the user values the significant cost efficiency of the AMD RX 6600 XT or the extensive hardware advantages of the NVIDIA GeForce RTX 5090D.