https://forums.lenovo.com/t5/X-Series-ThinkPad-Laptops/ThinkPad-CPU-run…
"Newer ThinkPads make use of high performance CPUs that may require more power than what the 65W adapter can provide while also supporting USB, Optical and other attached devices, especially in docked configurations. To prevent the potential for sudden system shut down if the power demand exceeds what the adapter can supply, the maximum clock speed may be limited when the system is operated on the 65W AC adapter and no battery is installed."
És egy hosszú lista a gépekről. Persze azóta jöttek ki újabb gépek, de azokra is igaz lehet.
Szerk, közben a support oldalon is megtaláltam:
http://support.lenovo.com/en_US/detail.page?DocID=HT075965