Pcie riser vs multiplier?

[Manny_NotTheStig]

Would be any performance loss or issues with lag with using a pcie 1x multiplier like this one [https://www.amazon.com/gp/aw/d/B075KNH1GM/ref=mp_s_a_1_17?ie=UTF8&qid=1515507708&sr=8-17&pi=AC_SX236_SY340_FMwebp_QL65&keywords=pcie+1x+multiplier&dpPl=1&dpID=41VwC9TCv0L&ref=plSrch]?

 

I'm working with an mATX board that i plan on having 2 graphics cards on, which would cover up the two remaining pcie 1x slots. I need those 2 slots for an external audio card and a pcie usb hub. It looks like it will be hard to get a riser cable from slot in between two 16x slots. So I'm wondering if i can multiple the bottom 1x slot.

[Thermosman]

Would work, but it would be bottlenecked I think

Edit: there are two 1x slots, why not get two single risers

[Manny_NotTheStig]

The layout on the mobo is 16x, 1x, 16x, 1x. I'm just wondering how the riser on the first 1x would wrap around the second gpu to get to the bottom of the mobo. Thats why I'm asking if a multiplier would be easier without issues.