ThinkPad P series
The P series was developed as a direct successor of the discontinued W series, but it no longer retains the structural and hardware similarity with the T series. Although, the slim models followed the W series' original tradition of upgrading the existing T series' chassis with faster graphics controllers.
This series was also the first ThinkPad line-up to feature rebranded mobile Core processors with ECC support (Xeon) as an option, allowing them to utilize ECC memory for environments that do not tolerate errors.