Pcie riser /splitter for 1u case

I am looking for pcie 8 to 4x/4x splitter. passive one, my motherboard supports bifurcation but my search results seem to yield no results. anything will be good. im using basic server motherboard with a integrated gpu with 32 meg of video memory. even xubuntu seems to be slugish on that system so i need a very basic gpu.

something similar that would split 8x slot into two 4x/4x slots.may be ribbon.bloody motherboard has a slot with a closed end and i cant use anything longer than 8x ;/

yeah seems like my only option is to use a tool on that slot ;/