Building Rig with 8 cards question

Building a rig with 3090, 3080TI, 3080, 3070TI, 3070, 3060TI, 3060, 2080TI all next to each other for comparison . My motherboard only supports 6 PCIe. If i use a splitter (4port riser print) does it affect the hashrate? The 3090 should arrive this week and i can start.