Intel serverboard negotiates only x1 lane for pci-e x8

hello.

mobo > intel s3000ah(v)

specs say there is one PCI-E X8 (with X8 lanes) available
intel specs

i have a asus with ATI RADEON HD3600 Series (3650) pci-e x16.
mobo has only x8 slot. i removed the ending part of the slot so the card would fit (the cut is clean and didn't touch the last pins).

the problem is that in windows 7 cpuz displays that the card is working in x1 lane, and capable of x16.
(clean w7 install - no drivers installed yet, but if i am correct that does not affect cpuz)

i would like to get the card working in x8 lanes.

thanks, thanks !