Budget mini-ITX ECC for GPU passthrough?

I need help with parts selection. I am trying to build a mini ITX system for GPU passthrough. I am hoping to have ECC as I would be able to use ZFS as well.

These are my requirements:

  • 2x GPUs(1 iGPU+dedicated GPU), would like to pair iGPU with Nvidia card for passthrough
  • ECC is preferable
  • mini ITX. As small footprint as possible

The issue I am facing is that AM4 APU platform does not support ECC. While ASRock Rack > X570D4I-2T is an option, it is an expensive motherboard and I will need to pair it with expensive ECC SODIMMs. Also I would not be able to use the host system when doing passthrough as the iGPU will not support 4K. Also cooler support, finding memory from QVL is a bit sketchy.

These are my rough parts list for non-ECC system(amount in Canadian Dollars pre-tax):

Parts list for ECC system(amount in Canadian Dollars pre-tax):

Which looks like a better option? Is there any other option here? I tried exploring getting Ryzen 7 4750G from Ebay. That looks like a great option but ECC support from motherboard vendors for it looks sketchy.

Thank you!

Looks like 4750G should support ECC with the Gigabyte board, but only 16GB RAM option is in QVL, meaning I would only be able to get 32GB max.

The Ryzen 7 5700G supports ECC if paired with a motherboard that supports this. Perhaps the Crosshair VIII Impact fixes this?

Is there any resource for this? Google search shows this isn’t the case: https://www.reddit.com/r/Amd/comments/owheh5/ecc_support_of_5600g/

This looks like an interesting option: Asrock Rack Server Riser Card/Accessories M2_VGA M.2 2280 B+M key VGA module - Newegg.com . Only using 1 GPU passthroughed VM at a time is a workable option and it is much cheaper than getting the Asrock rack mobo.

Sorry, you are correct. I wrongly assumed that, since the 4xxxG supports it, 5xxxG should too, but that motherboard support for ECC was scarce among ITX offerings in any case.

Anyway, don’t get too hung up on ECC memory, my company did some calculations and came up with the chances of RAM errors happening on desktop computers / workstations was once per year and a worst-case of two-three hours lost in productivity (best case was application crash and a loss of 15 minutes of productivity). It isn’t worthless but way overhyped for what it is.

For mission critical servers ECC is a must-have, but for workstation it is a nice-to-have.

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Unfortunately with Zen+/2/3 APUs you only get ECC when getting a “PRO” SKU, look for a “50” at the end of the APU model number, for example 4750G.

As far as I know the best APU for AM4 with ECC is the 5750G which is unfortunately extremely rare on eBay et al. - AMD is not releasing the PRO APUs on the retail market.

(Zen 3 APUs seem to not be getting the 3D cache performance bump as the last AM4 Zen 3+ (?) CPUs will be getting this holiday season)

Might be much easier to get a Zen 2 4750G. Still a solid option, about as fast as a 3700X.

Sadly, the APUs are locked down power envelope-wise, they’ll never go above 88 Watts PPT :frowning:

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Power lock isn’t an issue for me, I like low TDP parts. The issue is that even if I manage to find the processor, it’s hard to know if ECC would work with it as that is upto the motherboard manufacturer and the documentation about ECC working on the Pro APUs with non-OEM motherboards is sparse.

That’s what I am warming upto. Doesn’t look like there is viable alternative here without coughing up for the Asrock Rack motherboard. Even with that there are compromises.

I think I found the solution:

This case should support dual GPU with a M.2 riser which will goto the chipsets x4 pcie lane. That way I can have something like NVS510 for the display on Linux and dedicated GPU for Windows VM. Could IOMMU groupings be an issue with something like this? Also I’m not sure I can get a M.2 SSD without getting bottlenecked by throughput.

Yes. Bifurcation does not separate the IOMMU group so you will have to do the ACS patch.

Using the iGPU on something like the 5750G (which you likely can just salvage from an OEM system) won’t have IOMMU issues.

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Pardon me asking, but if you are going to go bifurb anyway, why not pair an mATX B550 with a Sliger Cerberus mATX or perhaps an mITX Sliger SM560 + bifurb riser? You could also go with the SM580, put in one single slot watercooled card bifurbed with one regular card, but that is a lot more hassle.

Specs for the various cases (mm for measurements, volume in liters):

Case Width Height Depth volume CPU height GPU length
NR200 185 mm 274 mm 360 mm 18.25 liter 76 mm 330 mm
Cerberus 172 mm 319 mm 358 mm 19.64 liter 75 mm 330 mm
SM560 159 mm 208 mm 208 mm 11.08 liter 55 mm 305 mm
SM580 155 mm 287 mm 357 mm 15.88 liter 55 mm 328 mm

Slinger cases+shipping is prohibitively expensive. I was thinking I would use the M.2 slot, not a bifurb riser.

Considering it, however the mobo ECC support for these isn’t well advertised. Also APUs seem to have bad IOMMU groupings from what I read online.

Older APUs do have bad IOMMU. But the 5700G has pretty good IOMMU from what’s been put out there.

If you’re really concerned, run your 2nd GPU in Gen4 x4 off of a X570 chipset.

Gotcha, thanks! I’ll keep an eye around eBay for these. I’m in no immediate hurry to build a system, especially considering the crazy GPU prices.