That's a Pentium M 755 2GHz processor - this should be a nice performance boost over the 1.5GHz chip that's currently fitted. It only took me two attempts to get one through eBay (first one evaporated without the tracking code ever becoming active).
To go with it I also have an uprated heatsink, though that's less for the CPU and more for the laptop generally - the graphics chip only has a pokey little passive heatsink and so gets quite toasty, leaving the fan running all the time trying to cool it and not really succeeding.
So, tonight's challenge is can boggyb replace the heatsink and CPU on a Thinkpad R50p and get everything else that needs doing done? Well, there's only one way to find out!