I have Lenovo ThinkPad X220 on which I am using the Synaptics UltraNav TrackPoint stick as mouse. Upgrade to Windows 10 made mouse slow enough to cause strain because of the extra force required, even when the Windows mouse speed setting was maxed out. In Windows 10 64-bit the latest UltraNav driver version 126.96.36.199 has no specific controls for changing TrackPoint sensitivity like there used to be with Windows 7. But the sensitivity setting still exists as a registry key, as I found out by adjusting it using UltraNav driver version 188.8.131.52 and monitoring the registry with Regshot. The registry settings still work with driver version 184.108.40.206 and can be changed using RegEdit, here to fastest possible, the way I like it:
Or you can just use this .reg file: UltraNavHack.reg. The setting will take effect if you visit Additional mouse options (even if you click cancel to back out).
The original value was 0x00000004. Don't fool around too much with different values, or you may have to reinstall the drivers.
Other ThinkPad models that may have this problem use the same driver version 220.127.116.11 and can be found listed in its readme: Helix, Helix 2nd Gen (Machine types: 20CG, 20CH), S1 Yoga, S430, T420, T420i, T420s, T420si, T430, T430i, T430s, T430si, T431s, T440, T440p, T440s, T530, T530i, T540p, T550, Twist S230u, Twist, W530, W541, W550s, X1, X1 Hybrid, X1 Carbon, X1 Carbon (Machine types: 20A7, 20A8), X1 Helix, X1 Helix 3G, X220, X220i, X220i Tablet, X230, X230i, X230 Tablet, X230i Tablet, X230s, X240s, X240.
Based on the comments this still works with the latest Synaptics ThinkPad UltraNav Driver for ThinPad version 18.104.22.168, which supports the following ThinkPad models: ThinkPad X1 Carbon 3rd Gen (Machine types: 20BS, 20BT), ThinkPad X1 Carbon 4th Gen (Machine types: 20FB, 20FC), ThinkPad X1 Tablet Gen 1 (Machine types: 20GG, 20GH), ThinkPad X1 Yoga Gen 1 (Machine types: 20FQ, 20FR), ThinkPad P50s, ThinkPad T460s, T560, ThinkPad X250.