Microsoft Surface Pro 6 and Surface Book 2 Are Throttle Locking To 'Pentium 2 Speeds' of 400 MHz, Users Say

intensivevocoder writes: Owners of Microsoft's Surface Pro 6 and Surface Book 2 systems are finding themselves stuck at Pentium 2 speeds, as numerous user complaints indicate that the ultra-portables are throttling the processor down to 400 MHz, a state that -- in some instances -- persists across reboots. While similar issues with Surface devices have occurred in the past, reports of issues have increased in frequency following a firmware update for the Surface Pro 6.

The throttle-lock appears to be caused by an Intel CPU flag called BD PROCHOT (bi-directional processor hot), which can be set by any peripheral, telling the processor to throttle down in order to decrease system temperature -- a useful flag in cases where the CPU is operating within thermal limits, but other components tied to the CPU are running too hot, because of the demands placed on other components by processes on the CPU.