I have burned my hands a couple of times buying hardware that does not support linux well.
I need some help to find a motherboard that shall be used i a “workstation”
The plan is to run linux of some kind and have that host a windows machine with a gpu passed through to it. Next to that it will probably run one or more vm with linux, at least one for NAS functionality and multiple dockers.
I plan to buy a AMD 3700 for now with option to upgrade to a 3950 when the get to the used marked.
The motherboard shall have support for 4 Dimms of ram and then as many pci 16x slots as possible and hopefully 2 m.2 slots.
On a mATX motherboard? This would be challenging. Most mATX only comes with one x16 and one or two additional pcie slots which would be lost if you want more than one m.2 slot. 4 Dimms is also rare and less important as memory capacity grows.
Given the newer CPU I’d suggest arch based os to maximise support for the features but generally running Linux on Ryzen is a solved problem.
Again a mATX will have limited data ports for a NAS and you won’t have spare slots for a HBA. Why do you need mATX form factor for this?
Go full size ATX. Look for a decent x570 board. Vendor of your choice but for 3950x you want decent vrms do look for something with “gaming” in the title.
Or go x399 and get a good deal on an older threadripper.
mATX and “as many pci 16x slots as possible” are two things that by definition don’t go together. mATX is specified with a maximum of 4 expansion slots. GPUs tend to go more towards the 3 slot usage per card and so motherboards are adapting to that.
Even assuming the board is made for 2-slot cards only, that gives you a maximum of 2 slots to work with, and manufacturers don’t tend to do that anymore.
Now pair that with the scarce availability of mATX for AM4 to begin with and you’re essentially looking at making your own motherboard.
Also… you do realise that those “x16” slots would only be mechanical and not eletrically x16, right? AM4 has 24 PCIe lanes to work with. 4 are specified to go to the chipset. 4 are typically reserved to PCIe-M.2 (although not specified to my knowledge), so that leaves you with 16 open PCIe lanes.
So even if defying all of the above, you will get a maximum of 16 lanes to work with.
Now… back to your question, how exactly would “as many pci 16x slots as possible” work? Because the maximum is 1. Yes, even on ATX and E-ATX boards. And that doesn’t even factor in your M.2 devices, unless you’re looking at SATA-M.2.
Well unfortunately in terms of m-atx am4 boards,
there isn’t really any decent choice in my opinion.
Because pretty much all m-atx am4 boards are just kinda rubbish.
Or lets say definitelly not really suitable for a 3900x / 3950x.
Because they are all weak in terms of the vrm.
For am4, i would just highly recommend to go with atx.
Also like @mihawk90 above already pointed out,
m-atx and as much as possible pci-e slots is kinda,
well not really a thing…
So yeah my recommendation go with ATX or E-atx.
Then you will have plenty of nice x570 boards to choose from,
depending on your specific feature needs.
I can see that my request for as many pci-e slots as possible has been misunderstood a bit. I do know the limitation on matx allowing for only 4 slots. i was hoping that i could get a board with 4 slots avilable and usable. i know that i might only get one electrically x16 and then the rest x1 but that should be enough for an HBA and a NIC of some kind. All at the same time as having two pci m.2 ssd’s running
The reason for me sticking to matx is basically that i like the size. not itx small and with out expandability and on the other not as big as atx.
I have two matx systems now which i was hoping to merge into one with my new build, so a at least could reuse one of the cases. But it sounds like im better of with a atx board and a new case.
Almost all boards have a spacing of x16 slots for 2 or 3 slot GPUs, and fill the space between with shorter PCIe slots. But as soon as you fill the x16 with a GPU, those will be unusable unless you are using one of the workstation 1-slot GPUs.
But you should also know that those are usually not PCIe 3.0, but 2.0, and go through the chipset. So depending on the bandwidth requirements for whatever you want to put in there, you might run into limitations because it’s a total bandwidth of just 3.0 x4 into the CPU.
Couple of points here. Most HBAs are x4 so would need a full length slot. Most mATX boards only have one full length slot that will have your GPU in.
Most mATX boards have up to 3 slots (x16 X1 X1) but that second slot will be covered by the GPU fan unless you get a single slot GPU or water cool.
Finally if you have 2 m.2 connectors active it may cut off bandwidth to the X1 connector in the bottom slot as there are only 24 pcie lanes.
Finally, just a general point about having your hard drives in your main pc for a hybrid Nas. This means keeping your main pc on all the time, whereas if you separate out the storage into a low power dedicated server, it will be quieter, cooler and enable better power efficiency.
Depends. Do you mean 1 x16 and 1 x4, and in addition to that an M.2? Or is the M.2 included? If it’s included then basically every board should have that.
If it’s not included you run into the lane limitations again (x16 + x4 + M.2-x4 = 24). If you only need 2.0 x4 that would work out as well, as every board should have something for that.
Things to keep in mind: VRM, Iommu groups. I’m building on an x470 aorus ultra gaming. I’ll have all the correct iommu stuff, but not the best vrm for the 3900x I’m getting. It’ll run just fine, but no overclocking, which I don’t really do anyways.
Not sure how you wanne achieve this on a m-atx am4 board?
Because you basically going to need 2 gpu’s if you wanne do that properly,
unless you go with a apu.
Because then you could use the internal gpu part of the cpu to run the host linux machine on.
Still like i said above, all matx am4 boards are just garbage.
So yeah i would say just go atx, if you want to stay with Ryzen.
Non of the matx am4 boards will be suitable for a 3900x / 3950x.
If you trully wanne do pci-e passtrough vm on a matx platform,
then just go intel z390 m-atx board with a 9900K cpu.
Because the 9900K comes with a igpu, and that can be used to run the linux host machine on.
So in that situation you basically only need one dedicated gpu to pass trough.
Also intel in general works pretty well for virtualization and pci-e pass trough.
But if you wanne stick to Ryzen with a 3700x and later on a 3950x.
Then atx is pretty much your only viable option. The Asus WS X570 Pro Ace might be the ideal board for you then.
