In BIOS, Advanced > Chip Configuration you can set AGP Capability (2X, 4X) and Graphics Window Size (4Nb, 8Mb, etc.)
The CUV4X is a good board for overclocking but there seems to a limitation regarding core voltage. Someone reported that the CUV4X always boots at default vcore and then changes to whatever is set in BIOS. I don't know if this is correct but there is something odd. I can boot 927MHzs at default (1.7v) but not 945MHz. If I boot at 927, enter BIOS, change to 945 and 1.9v, then the next boot is okay. I'm up and running Windows NT stable at 945MHz. But if I now reboot, the machine will not post. I have to restart again at default settings (600MHz).
Also the CUV4X has dip switches for bus clock and multiplier but nothing for vcore (BIOS settings only).