1. Substitution Analysis for 71V65603S133BQG From the perspective of core electrical parameters and physical packaging, the 71V65603S133BQG can serve as a direct replacement for the original part 71V65703S80BQG. Both devices are identical in memory density (9Mbit), organization (256Kx36), operating voltage (3.3V), and package (165-TBGA), ensuring full hardware compatibility. The key difference lies in performance: the substitute part features a clock frequency of 133MHz and a significantly faster access time of 4.2 ns compared to the original's 8 ns. This results in higher data throughput and faster system response, offering a direct performance upgrade when used in the existing system. Provided the system's host controller can support and be configured for a 133MHz or higher clock frequency, this substitution is fully viable both functionally and physically, representing a performance upgrade. 2. Substitution Analysis for 71V65603S150BQGI The 71V65603S150BQGI is also a viable replacement candidate for the original 71V65703S80BQG. Its fundamental compatibility parameters—density, organization, voltage, and package—are identical to the other parts discussed. The performance differential is even more pronounced: it operates at a higher clock frequency of 150MHz and achieves a further reduced access time of 3.8 ns, making it the fastest device among the three. It offers the highest data bandwidth and the lowest access latency. Furthermore, the suffix "I" typically indicates support for an extended industrial temperature range, which may provide superior reliability compared to the original commercial-grade part. This substitution therefore represents not only a direct performance upgrade but also potentially improved environmental robustness. The prerequisite for successful implementation remains the system controller's ability to support operation at the 150MHz clock rate.