AMD “Zen3” processors feature a new technology called Predictive Store Forwarding (PSF). PSF is a hardware-based micro-architectural optimization designed to improve the performance of code execution by predicting dependencies between loads and stores.
Security research in recent years has examined the security implications of various CPU micro-architectural optimizations.. In particular, programs that implement ‘sandboxing’ entirely in software may need to be concerned with PSF behavior.
AMD CPU architects write about PSF in a paper describing how PSF works, potential security concerns, and available mitigations. The paper is available here.