The NVIDIA RTX 4090 is the objective winner of this comparison, securing victory in ten out of thirteen measured categories. Its most significant technical advantage is its FP32 performance, which is 1418% higher than that of the alternative. While the NVIDIA GTX 1660 Ti maintains a lead in three specific areas, the substantial performance gap in computational throughput establishes the RTX 4090 as the superior component based on the provided specifications.

Users prioritizing raw computational power should select the NVIDIA RTX 4090 to leverage its massive advantage in FP32 performance. Conversely, the NVIDIA GTX 1660 Ti is the appropriate choice for buyers who prioritize a lower MSRP, as it holds an 83% advantage in that category. Your decision should depend on whether your primary requirement is the high-end processing capability of the former or the cost-focused positioning of the latter.