Hi everyone,
I’m trying to run a true dual discrete GPU setup (no iGPU) on a Minisforum BD895i-SE ( BD795i-SE - same motherboard basically) and hitting a wall with pcie connection setup and device detection.
Hardware:
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Motherboard: Minisforum BD895i-SE ( Ryzen 9 8945HX ) or BD795i-SE equivalent
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Bifurcation card: 10Gtek PCIe 5.0 x16 → 2× MCIO 8i ( XRET5032 retimer chip, slot-powered only )
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Cables: standard SFF-TA-1016 MCIO cables ( 50 cm )
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Two downstream adapters: MCIO-to-PCIe 5.0 x16 full-height boards (each with own aux power)
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GPUs: 2× AMD AI PRO R9700 ( ≈300 W each, RDNA4 )
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PSU: be quiet! Power Zone 2 1200 W ( native 12V-2×6 connectors + dedicated power lines to each downstream board )
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BIOS: 1.15, bifurcation set to x8/x8 ( tested Auto / Gen5 / Gen4 / Gen3 ), iGPU + Hybrid Graphics disabled, ReBAR enabled
Problem:
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Single R9700 ( direct in slot or any side of bifurcation ) → works perfectly ( Gen5/Gen4 x8, full speed in lspci )
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Both GPUs powered on → only one card enumerates randomly ( lspci shows only one device ) . The other card doesn’t show up at all. Unplugging power from one GPU makes the other work instantly. This happens 100% of the time, no matter the order of permutations.
I already ruled out basic power delivery ( PSU is overkill, every component has its own aux power ).
Question:
Has anyone here successfully run two discrete GPUs on the BD895i-SE / BD795i-SE using a retimer/MCIO bifurcation setup?
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Which host bifurcation card worked for you? ADT-Link / JMT F36B-F37B-D8S with aux power? LR-Link LRSV9501-2E? C-Payne? something else?
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Did you need to drop to Gen4 or were you able to stay on Gen5?
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Any special BIOS tricks or kernel parameters that made dual dGPU stable?
I’m trying to avoid dropping $1500+ on a full desktop AM5 platform ( B850 AI TOP + 9900X + DDR5 ) if I can salvage this setup with a better-powered retimer card < $300. Would really appreciate any real-world experience.
Thanks in advance — this forum has saved me many times before!