hi ecd2112, a more practical approach to gain performance is still:
1. invest in an SSD;
2. do a fresh windows install, with only necessary drivers.
clearing up bloatware do save you space, but the performance gain is somewhat little. but if you insisted, here is the list of drivers and stuff that i think important:
1. Intel INF Update Driver
2. Via Audio Driver
3. nVidia Graphics Driver
4. Athros LAN Driver
5. Alcor Multi-Card Reader Driver
6. Synaptics Touchpad driver
7. Intel USB3.0 Driver
8. ASUS Wireless Switch (Wireless Console3) Utility
9. ATKACPI driver and hotkey-related utilities
10. Nvidia PhysX Utility
11. Power4Gear Hybrid Utility
12. Keyboard Device Filter Utility
13. Wireless driver
14. Bluetooth driver
15. Intel Management Engine Interface
16. The Turbo Boost application
17. Intel Rapid Storage Technology driver
other than that, they can be removed safely.