The first ThinkPads contained a variety of processors from different manufacturers like Intel, Via, and IBM themselves. But with the start of the Pentium era, IBM focussed on Intel and hence almost all ThinkPads since then feature Intel processors. The only exceptions are the three PowerPC based models of the 8xx series.
In June 2000 IBM presented a prototype of the ThinkPad 240 featuring a Transmeta Crusoe 5600 processor. These notebooks were planned to hit the market in the forth quarter of that year, but in October IBM dropped their plans and opted for Intel instead.