I’m currently running a Xeon E3-1231v3. It’s getting long in the tooth, supports only 32GB RAM, and has only 16 PCIe lanes. I’ve been butting up against the platform limitations for a couple of years now, and I’m ready to upgrade. I’ve been running this system for ~10yrs now.

I’m hoping to future proof the next system to also last 8-10 years (where reasonable, considering advancements in tech and improvements in efficiency), but I’m hitting a wall finding CPU candidates.

In a perfect world, I’d like an Intel with iGPU for QuickSync (HWaccel for Frigate/Immich/Jellyfin), AND I would like the 40+ PCIe lanes that the Intel Xeon Scalable CPUs offer.

With only my minimum required PCIe devices I’ve surpassed the 20 lanes available on desktop CPU’s with an iGPU:

  • Dual m.2 for Proxmox ZFS mirror (guest storage) - in addition to boot drive (8 lanes)
  • LSI HBA (8 lanes)
  • Dual SFP+ NIC (8 lanes)

Future proofing:

High priority

  • Dedicated GPU (16 lanes)

Low priority

  • Additional dual m.2 expansion (8 lanes)
  • USB expansions for simplified device passthrough (Coral TPU, Zigbee/Zwave for Home Aassistant, etc) (4 lanes per card) - this assumes the motherboard comes with at least 4-ports
  • Coral TPU PCIe (4 lanes?)

Is there anything that fulfills both requirements? Am I being unreasonable or overthinking it? Is there a solution that adds GPU hardware acceleration to the Xeon Silver line without significantly increasing power draw?

Thanks!

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13 points
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iGPU is just integrated GPU on the CPU die. That is going to use pcie lanes for communication.

Wiring up a iGPU, as a cpu architect, you have two options:

  • direct interconnects (low latency, no space, no extra heat)
  • MUXed interconnects (latency, complexity, space, and heat on die), but even then you would have to choose between using the iGPU and having external PCIe lanes anyway

I think most designers have gone with direct interconnects

Sounds like your real requirement is just more pcie lanes, I believe epyc chips will provide in abundance

https://www.amd.com/en/products/processors/chipsets/am5.html

You can look at pci-e lanes available by model here.

Also you can use newegg to search moterboards by usable pci-e lanes.

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3 points

Thanks. I’ll be the first to admit a lack of knowledge with respect to CPU architecture - very interesting. I think you’ve answered my question - I can’t have QuickSync AND lanes.

Given I can’t have both, I suppose the question pivots to a comparison of performance-per-watt and number of simultaneous streams of an iGPU with QuickSync vs. a discrete GPU (likely either nVidia or Intel ARC), considering a dGPU will increase power usage by 200W+ under load (27c/kWh here). Strong chance I am mistaken though, and have misunderstood QuickSync’s impressive capabilities. I will keep reading.

I think the additional lanes are of greater value for future proofing. I can just lean on CPU without HWaccel. Thanks again!

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4 points

If power consumption is an issue then I’d recommend the arc a310 which can only draw up to 30 watts. I’ve been using one for a while and it can easily handle several 4k streams without issue.

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2 points

Thanks. This is a pretty compelling option. I hadn’t looked at the entry level arc, but when it comes to encode/decode it seems all the tiers are similar. 30W is okay, and it’s not a hard limit or anything, just nice to keep bills down!

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