Variation in c0 state versus full utilization achieved by certain tasks
Variation in c0 state versus full utilization achieved by certain tasks
I have adequate cooling for my i5 9600kf. The temperature stays around 60°C or close to it, especially when the CPU is idle. When I play games, I turn off the idle saver. I understand that in C0 mode the CPU is fully prepared and ready to run tasks, so it should heat up as expected if it were working at full capacity. However, even during my idle periods, temperatures remain low—around 60°C, which was normal in summer. Recently, while doing intensive tasks like folding images, the temps rose to 72°C on all cores, which is still within safe limits. I’m wondering why this happens. I thought C0 mode should behave like a full workload, causing higher heat, but it doesn’t seem that way. It’s possible the voltage increases more when actual code runs.
State 0 is processing commands right away. Certain instruction types take more CPU power, which usually leads to increased heat, commonly observed with AVX operations. Indeed, during heavy demand, all X cores may shift to State 0, while other cores or threads stay idle in a standby condition known as State 2.
C-state 0 indicates the central processing unit is operating normally without any power-saving techniques. In this mode, the CPU continuously runs minimal "wait" operations per clock cycle, consuming relatively low energy compared to fully powered states. Voltage levels remain stable as long as AVX instructions aren't executed. As noted by @ShrimpBrime, various instructions draw different power levels and engage different parts of the core. Overall, power consumption depends not just on clock speed, voltage, or state, but also on instruction complexity.