1. Substitution Conclusion for 71V65703S80BQGI8 From an electrical compatibility and physical footprint perspective, this part can be considered a "drop-in replacement" for the original component. Both share identical core architecture (SDR ZBT), density (9Mbit), organization (256K x 36), voltage range (3.3V ±5%), and package (165-CABGA). However, a critical performance downgrade renders it an unfeasible direct substitute in most applications. The key difference lies in the access time, which is significantly degraded from 3.8ns to 8ns. This directly reduces the maximum stable synchronous operating frequency (clock frequency) from the original 150MHz to a typical value of approximately 125MHz or lower. If the original system design relies on the 150MHz high-speed data throughput, switching to this slower part will fail to meet timing requirements, potentially causing system instability or functional failure. Its use should only be considered in systems with exceptionally large timing margins or where the operating frequency has been deliberately down-clocked.