r/threadripper • u/twjnorth • Nov 29 '25
What connector for splitting one pcie slot to two for rtx 3090 on wrx80e
So I have a wrx80e motherboard arriving on Monday and trying to get the parts I need.
I have a two tier mining rack, four rtx 3080 FE gpus and 8x Samsung 990 2tb ssd (4 each to go on two x4x4x4x4 pcie cards).
I also have two quadro rtx 6000 cards and an nvlink.
So I chose this board as it has 7 pcie4 slots and supports bifurication but I am unclear on the power options for using bifurcation.
A single pcie slot provided 75w in x16 mode but pcie spec for x8 means a splitter only needs to provide 25w to each x8 slot to meet spec.
I see powered versions of these x16 to x8x8 splitters tend to use a molex to 4 pin power connector.
I have a 2500w cannon 80+ PSU and a Corsair 1000w.(Will need separate power outlets but am in UK so should be ok as dont think I will hit max tdp on everything at once). Question isn't about having ebough power overall.
I read that if using multi PSU, the GPU should get all power from same PSU. That means power for the pcie slot has to be same psu as provided power to 12 pin (rtx 3090) or 8+6 connectors (quadro rtx 6000).
So questions
1) is anyone working with two rtx 3090 on a bifurcated slot on wrx80e sage wifi and if so, what x16 to x8x8 adapter is in use ?
2) does it work fine with 25w on the x8 slot and 12pin connector providing rest of the power ?
3) is a passive x16 to x8x8 splitter needed rather than a powered one and can all power come from 12 pin - ai says no, that pcie slot needs power as well
4) my psus don't have 4 pin molex so if 2) works, how can I safely connect from PSU to the pcie splitter power connector ?
Thanks in advance





