The variable-input look-up table (LUT) architecture has been a fundamental component of the Xilinx Virtex architecture first introduced in 1998. This unique architecture enables flexible implementation of any function with eight variable inputs, as well as implementation of more complex functions. In addition to being optimized for 4-, 5-, 6-, 7-, and 8-input LUT functions, the architecture is designed to support 32:1 multiplexers and Boolean functions with up to 79 inputs. The Virtex architecture enables users to implement these functions with minimal levels of logic. By collapsing levels of logic, users can achieve superior design performance. This performance leadership is validated by benchmarks that show Virtex with an average 38% performance leadership over alternative programmable logic architectures.