So how does boost work in this case? Put simply, the PlayStation 5 is given a set power budget tied to the thermal limits of the cooling assembly. "It's a completely different paradigm," says Cerny. "Rather than running at constant frequency and letting the power vary based on the workload, we run at essentially constant power and let the frequency vary based on the workload."
An internal monitor analyses workloads on both CPU and GPU and adjusts frequencies to match. While it's true that every piece of silicon has slightly different temperature and power characteristics, the monitor bases its determinations on the behaviour of what Cerny calls a 'model SoC' (system on chip) - a standard reference point for every PlayStation 5 that will be produced.
"Rather than look at the actual temperature of the silicon die, we look at the activities that the GPU and CPU are performing and set the frequencies on that basis - which makes everything deterministic and repeatable," Cerny explains in his presentation. "While we're at it, we also use AMD's SmartShift technology and send any unused power from the CPU to the GPU so it can squeeze out a few more pixels."