Optiplex 7080 vs Optiplex XE4:BIOS Intel SpeedStep:Disabled problem

The attached picture show:

Left side: Optiplex 7080 BIOS,Intel SpeedStep disabled and it has disabled description:Highest  CPU performance and in windows OS it exactly shows the highest CPU speed.

Right side:Optiplex XE4,Intel SpeedStep disabled ,but where's disabled description? and strangely in windows OS,CPU speed is limited below the base speed 2.1Ghz.

For SpeedStep:Enable

Optiplex:7080 CPU speed is still set to the highest 4.59Ghz and no floating.

Optiplex:XE4 CPU speed is floating ,but it can exceed base speed 2.1Ghz to 4.3Ghz

How to make XE4 Intel SpeedStep:disabled and CPU speed set to the highest one?

It's a pity both Dell Japan and Dell China customer support ain't able to solve this problem,

And Dell China asked to upgrage BIOS, doint CPU stress test,changing to different OS version(Win10 IOT Ent 2021 LTSC High End to Win10 Pro) are to no avail.