need help with 2 p104-100 8gb gpus on ubuntu 16.04

I use a p104-100 for gaming on ubuntu 16.04 with nvidia 418 driver in prime with a coffee lake cpu's igpu. I recently started recording my gameplay for youtube, and noticed the screen recorder uses about 15% gpu at 1080p 30fps for the recording with an overclock to 2100mhz from 1933mhz stock at pci X4. my old p106-100 ran at x16 pci, so i know the display isn't making it run at pcix4.

i originally got 2 p104-100's to upgrade from the p106 and run in sli, however sli is pretty much non exthistant on linux. when i put 2 p104's in the system it force disables coolbits. my msi cards have really bad stock fan curves, so that and lack of overclock hurt performance by quite a bit.

since these are mining cards, and the 8gb bios hack was first discovered on the site as far as i know i figured here would be the best place to ask.

has anyone gotten these cards to run at pcix16 with 8gb bios mod? or figured a way to enable coolbits for both gpus with prime enabled? thanks.

i don't know if its helpful to know,but when i put the hdmi into the msi card it black screens until i move the hdmi back into the igpu/motherboard one. even in bios.