@Forestofenchantment The QM wasn't a common mobile chip, it was usually used as an option or on the mobile workstations, gaming laptops, higher end consumer laptops, etc.

Chances are you had the dual core back in the day, but there was one difference. You could only swap CPUs on the Haswell PGA systems like the Thinkpad T440 (not the T440s).

With Skylake and Broadwell, you could no longer do this. You were 100% stuck with whatever CPU was soldered unless you had BGA desoldering gear and could put in all that effort for a CPU upgrade (some X220 owners do this for quads).
image.png
image.png
image.png