Web browser are traditionally benchmarked using user-centric page-load times. We found such metrics inaccurate from an architectural perspective, and limit hardware and systems optimization efforts, for performance and energy efficiency. In this article, we introduce SysPLT , an accurate and stable metric targeting system optimization for browsers. SysPLT tracks page load time based on browser’s architectural activities. SysPLT captures on average 2.29× micro-architectural events compared to existing user-centric metrics, and provides insights to correct counter-intuitive system design choices recommended by user-centric metrics. We also show that SysPLT is more stable across repeated runs and different machine settings.