Stock speed means:
The official speed that was set by the manufacturer (no overclock).
That is the default speed that the product will run at out of the box.
In most CPUs cases, the Turbo speed is a default behaviour.
Stock speed refers to the default speeds a particular CPU uses, right out of the box, with no changed settings. Typically, you'll have a base and boosted/turbo speed. No user define settings applied.
I saw a post regarding PSU for high-end CPU coupled with high-end GPU. It says, a 850W Gold plus is pretty stable for i9 13900K and RTX 4090 at stock speed. I just wondered if it is true. i9 13900K is a power hunger CPU and RTX 4090 could draw up to 450W or more.
I think you need to go higher abit with the PSU around 1000W-1200W because both of them are good and work great with each other but think power will be squeeze with all your other parts.
Every Brand has there way making there PSU and some off them can be made for just med spec computers or low spec or high spec and you could buy 850W PSU but it been made cheaper or it could been made better so do not pick any PSU because it says 850W gold it depends on the bullt and reviews on them also the features on the unit.
Example go to shop one day and you buy PSU and couple months later it pops good quality PSU will have good protection or cheaper quality PSU will just destory your parts
Here diffrent types off PSU ATX 3.0 will have direct cable to plug into PSU to 4090 directly without adaptor