My Cpu i5-8250U
https://ark.intel.com/products/124967/Intel-Core-i5-8250U-Processor-6M-Cache-up-to-3_40-GHz Intel® Core™ i5-8250U Processor (6M Cache, up to 3.40 GHz) Product Specifications
TDP-Up = 25W
TDP-Up increase after update fix error "Spectre" and "Meltdown". TDP-up = 44W
I need an explanation!
I use Laptop Hp Probook 450 G5
https://support.hp.com/us-en/drivers/selfservice/swdetails/hp-probook-450-g5-notebook-pc/17047142/mo... HP Software and Driver Downloads for HP Printers, Laptops, Desktops and More | HP® Customer Support
I use TDP-ups? 44W or 25W !!
XTU was not designed to be reflective of cTDP-up. The Turbo Boost Short Term Power Max value you have highlighted is a different limit that's commonly used for overclocking. The 2 values (cTDP-up and Turbo Boost Short Term Power Max) do not need to be the same.
Here's some additional information on how cTDP-up works:
Intel Sky lake\Kaby Lake\Coffee Lake BIOS programming recommendation for cTDP_UP is to resolve the PL2 value from CONFIG_TDP_LEVEL2_MSR_0x64A. Expectation is that BIOS will end up programming up to PKG_TDP_LVL2 * 1.25 as the PL2 value.
In your case the processor has a 25w cTDP PL1 value. BIOS would then program up to a 30w PL2 value if the design of the form factor can allow for it.