Technically undervolting does not slow down the chip. The default turbo ratios on the 13900k are 5.8 GHz on up to two cores and 5.5 GHz on an all core load. The chip can do this stably at a given minimum voltage.
The problem is that the default voltage on current bioses is not the stable minimum, and are unfortunately way way higher than they need to be. For instance, Asus sets the default voltage on formula to over 1.4 volts. But when an all core load is applied, the Asus default voltage results in power consumption of over 300W with temps approaching 100C.
But by undervolting, you find the minimum voltage for Stable operation. On my 13900K this minimum seems to be around 1.27-1.28V (with a load line of 3). At this voltage, the chip doesn’t slow down and boosts to the default frequencies. But consumes much less power and as a result run cooler as well. So same performance, less watts and less temps.
By undervolting, I was able to shave 40-50W off, and reduce temps by 22 degrees compared to “stock.” Some 13900K chips have a higher SP rating than others, and can sustain higher frequencies at lower voltages (and power consumption) than others. This is where binning comes in.
I am using a kraken z73 360 mm cooler but I don’t need anything more than a 280mm honestly.
