[SOLVED] 9900k cores keep jumping to 60C idle

[TheMrFerrari]

Core 0, 1 and 2 keep jumping from 40C to 60C for a couple of seconds randomly while idle, then they return to 40C. Why does this happen? (I know the 40C idle temp isn't too good either, I'm planning to buy an AIO in the near future)

 

[TheMrFerrari]

I forgot to say, I don't have any overclock

 

[Phaaze88]

Core 0, 1 and 2 keep jumping from 40C to 60C for a couple of seconds randomly while idle, then they return to 40C. Why does this happen?

There's always any number of background activity going on - the system is never truly idle.
The tasks themselves aren't very demanding, so the few active threads boost to their highest speed to get it over and done with, and they go back to rest at a lower speed until it's needed again. It's to save power.
That's what's happening during those 'jumps' and it's normal.

I know the 40C idle temp isn't too good either

Says who?
It's just the norm for your particular setup. As long as it's not blowing over 85C under load... Idle thermals will be a reflection of:
-Room ambient temp; the air inside the chassis is always warmer.
-The hardware packed inside the chassis.
-Motherboard settings.
-Windows power settings.
-How efficiently air gets in and out of the chassis.
40C idle? /yawn

I'm planning to buy an AIO in the near future...

That's not a guaranteed fix for something that may not need fixing.
Do load thermals warrant a cooler change?

 

[mdd1963]

If you observe HWmonitor and carefully look at task manager/processes, you will see the above hypothesis is quite correct; my own 7700K will jump from 1.13 GHz to 2 GHz, to 3.8 GHz (occasionally even to 4.7 GHz)over the course of 2-3 seconds (once per second fluctuations are all that are shown on many monitors, but, the clock speeds change even more rapidly, and, with those clock speeds (with raised core voltages to support the targeted speed) temps rise /fall almost instantly in lock step with clock speed and load on the CPU...