Intel Extreme utility. Download it. Run Benchmark… It shows you quite a few things including, Thermal throttling, Power limit throttling, Current limit throttling.
VRM: Voltage Regulator Module. The Square things and capacitors near the CPU.
For years all we cared about was CPU thermal throttling but we have super coolers now, it’s not an issue. The real issue is keeping the VRM’s cool or how well they can regulate the power going to the CPU. The better it can do that, the more stable your OC will be.
You could buy a 9900k but unless you put it in a flagship motherboard it won’t be getting the power it needs to run at all cores 5+ and HT.
I can clock my 9700k easily to 5+ but running the utility it clearly shows me that i get Current limit throttling. The motherboard can’t give it enough juice at a stable level. We only get slight flashes of throttling but in audio this wouldn’t be good.
My 9700k is set at all cores 4.9 and I’m yet to get past 30% on CPU usage in my projects… I don’t do anything fancy though, simple dance, rave music.