When Entropy Fails: The Hilarious (and Harmless) Zen 5 RNG Debacle
In October 2025, AMD quietly confirmed that its upcoming Zen 5 CPUs shipped with a broken hardware random number generator. The RDSEED instruction, designed to produce true entropy, was returning zeros while signaling success. AMD’s solution was to disable the feature entirely, turning it into a no-op. Fortunately, modern operating systems no longer depend on a CPU’s RNG alone, instead mixing multiple entropy sources through cryptographically secure algorithms. Zen 5’s RNG bug is embarrassing, but thanks to robust kernel design, it’s more of a punchline than a catastrophe.