Benchmarking 25 compiler flags for running Gemma 4 on a 2016 Xeon: 12 were useless, 2 made the difference

A follow-up technical deep-dive where the author systematically tests each of 25 compiler flags used to run Gemma 4 (a 26B-parameter AI model) on a 2016 Xeon CPU with no GPU and 128GB DDR3 RAM. By isolating flags one at a time across 174 restarts, they discovered 12 flags did not