getting from agp 1x to 2x

I have enabled my agp, but is running only 1x mode even though my chipset and motherboard supports both 1x and 2x.
I have been into my bios and set AGP Mode2x, but my read out still says only AGP 1x is enabled, even though I could support 2x.
How do I get from 1x to 2x?
Ny sidebanding is still disabled even though it is supported, but fast-write not supported.
I am sure it may be something simple, but I already have a bios disastr, and I do not need another one.
For everyone’s information in my bios there is not “agp video”.
Thanks for any help
Wilbur Huck