CPU performance is tricky to test these days, as CPUs of the same type can deliver vastly different performance numbers depending on the cooling and other outside conditions.
With recent ThinkPad laptops from Lenovo, it turns out that one of these outside conditions is the place where the laptop is used: The systems use the Intel "Dynamic Platform and Thermal Framework" (DPTF) to regulate the CPU performance based on if the system is used on a desk or on the users lap. On the desk, the CPU can reach much higher clock-rates, which leads to higher outside temperatures. On the lap, the CPU is limited to its basic TDP, enabling lower temperatures.
This sounds like a useful feature. The problem is that it only works correctly when Windows is installed, as DPTF requires several drivers to work. With an alternative operating system like any Linux based OS, it won't function correctly. The system is unable to recognize in which mode it should run and the CPU is locked down to the lower "Lap mode" performance.
That is why many ThinkPad & Linux users have been complaining about a lower than expected CPU performance in Lenovo's own support forum. After more than a year of complaints, Lenovo has finally admitted to this issue and thankfully also presented the prospect of a solution: The Chinese manufacturer will develop a firmware update for recent ThinkPad laptops that will basically emulate the Intel DPTF function on systems like Linux.
It is unclear which ThinkPad systems are affected by this problem. Some of the systems named in the Lenovo forums thread include the ThinkPad T480, its successor ThinkPad T490 and the ThinkPad P53. Another popular model with this problem is the Lenovo ThinkPad X1 Carbon 2019. This model appears to be the first one which will receive the fix from Lenovo.