CPU locked at 0.79 GHz from motherboard VRM PROCHOT throttling
A malfunctioning motherboard temperature sensor or overheating voltage regulator module (VRM) signals an artificial BD PROCHOT alarm, forcing the processor multiplier down to 8x (0.79 GHz).
Internal desktop parts run on harmless 12V DC voltage and cannot shock you. Simply unplug the wall power cable first, then touch the unpainted metal case frame to ground static electricity.
Common Symptoms & Tells
- Task Manager shows CPU Speed permanently pinned at 0.79 GHz or 0.39 GHz
- Computer feels excruciatingly sluggish even when completely idle
- CPU temperature in HWInfo is low (35C) but processor will not clock up under load
Interactive Fix Checklist
0 of 4 steps completedInspect motherboard VRM temperatures in HWInfo64
Download HWInfo64 (Sensors mode) and check 'Motherboard / VRM' temperatures. If VRM exceeds 105C, improve chassis intake airflow across the CPU socket area.
Perform a full power drain to reset sensor latch
Shut down the PC, disconnect AC power, and hold the power button for 30 seconds. On laptops, disconnect the main battery and hold power for 30 seconds to clear stuck EC sensor flags.
Disable BD PROCHOT with ThrottleStop (diagnostic verification)
Download ThrottleStop, uncheck 'BD PROCHOT' (Bi-Directional Processor Hot), and click 'Save'. If CPU frequency immediately shoots back up to 4.0+ GHz, a faulty motherboard sensor is triggering false alarms.
Update motherboard BIOS or RMA defective motherboard
Flash the newest motherboard to patch EC sensor bugs. If throttling persists on a desktop with normal temperatures, the motherboard VRM sensor has suffered hardware failure.
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