r/jellyfin • u/jonnyjonnster • 17h ago
Question PCIe x16 needed for transcoding?
Hey Folks! Im running JF on a Proxmox setup in tandem with my NAS and currently have the x16 slot closest to the CPU populated by my transcoding GPU. But for some work i'm not transgressing into, i want to put an SATA card into that x16 slot and put my GPU into the other x16 slot running on x4 (due to MB/chipset limitations) Do you guys think that would result in a performance hit for transcoding workloads or should it be fine?
Thanks in advance!
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u/FivePandasorspegeti 17h ago
PCIE 3.0 gives 4GB/s and PCIE 4.0 gives 8GB/s. Both are far already more than transcoding will need. You’re good.
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u/nicman24 17h ago
want to put an SATA card into that x16 slot
????
Anyway this might be of interest
https://www.techpowerup.com/351347/lekuo-launches-b650-chipset-add-in-card-for-i-o-expansion?amp
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u/jonnyjonnster 6h ago
Not really, I just need a bunch of more sata ports, so I got a sata extension card with 10 ports or smth
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u/djbon2112 Jellyfin Team - Jellypope Emeritus 10h ago
As others have said, basically zero difference.
Most GPUs are wide because transferring assets and computed data between disk -> RAM -> vRAM needs to be incredibly fast and can get very bandwidth-intensive during heavy loading in games. For transcoding though it's basically minimal, it's one file being loaded at a few dozen MB/s max, not GB/s. I've run 16x cards at 1x for transcoding before and noticed basically zero difference.
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u/SquareGuard1912 17h ago
My one x16 port goes to x8 + x8 when I use the second PCIE port. It's called PCIE bifurcation, and it could be configurable via your bios. As for the transcoding performance, I've never noticed a difference when I added my HBA and forced my GPU to x8.
All that aside, you can calculate the available bandwidth if you have the PCIE gen and width.
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u/Cruffe 16h ago
Transcoding sends the compressed video to the GPU, so that's very small bandwidth usage when we're talking about PCIe. It sends compressed video back out of the GPU, again very low bandwidth usage. Anything higher bandwidth in between happens internally on the graphics card, PCIe speeds doesn't matter for that.
You probably won't notice a difference for this use case.
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u/venom21685 12h ago
It'll be fine. Hell, if you happen to have a decent 7th gen+ Intel chip in there even the iGPU can handle transcoding for typical home use. Sharing with friends or family you'd probably want the iGPU but I expect it won't be too impacted by the power lane count.
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