Multiplier question, bios or hardware... ?

I own an old AOpen AX64 MoBo. I know a bios update can't give me a wider
range of possible FSB that Bios offers because these are the only ones
supported by the clock generator of my motherboard (ICWorks W144H).

But, is the clock multiplier a bios issue or is it related to hardware as
this is the case for FSB?

The Max multiplier for this motherboard is 8, Unicore software tell me that
there is a new bios for this MoBo but never replied my mail when I asked
what they mean by "support for faster CPU" so I want to know if this is
possible or not.

Thanks