V.Control is a free software which gives direct hardware control to your video graphics adapter; enabling custom refresh rates in increments of 1 Hz, over clocking without rebooting windows, and modifying PCI/AGP hardware configurations. Also provided are various registry tweaks. Currently supported are: 3dfx Voodoo Banshee, 3dfx Velocity, 3dfx Voodoo3, 3dfx Voodoo4, and 3dfx Voodoo5 (Voodoo5 6000 is untested). V.Control will also save and restore positions of desktop icons for any video graphics adapter.
Limitations: This software is beta and may be unstable.