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Comment by Kerrick | Hacker News Reader

That's another thing that bothers me about motherboard manufacturer's choices around PCIe -- one that I didn't cover in the article. Why on earth are they choosing (even on EATX motherboards) to put the extra PCIe slots within 1-2 spaces of the primary GPU slot, when they are so incredibly likely to be covered up? Instead, that's a great place to put the M.2 slots. Move the few remaining PCIe slots down, so they can actually be used.

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Unfortunately you cannot actually "move the slots down" due to how motherboards and CPUs work and still keep everything compliant and correctly timed. You can put in a PCIe extender, stiff (daughterboard) or flexible (ribbon or bracket) which works, but you are playing the game of "it might work, it might not" and juggling three variables of motherboard timings/quality, PCIe card timings/quality and extender quality. You don't know if it'll work until you try it. There's multiple reasons why those slots are where they are.

I have two ASUS dual CPU workstation motherboards and run some of the devices with PCIe ribbon extensions. I cannot run my Highpoint U.2 RAID card on an extension but I can run a Highpoint USB 3 card just fine. I can run a 2070 GPU just fine, but the RTX A5000 GPUs are flakey. The dual Blackmagic quad 4k capture cards want to be in specific motherboard slots and work okay on one particular brand (Thermaltake) of extension cable.

The problem is nuanced.

m.2 can get hot, installing them under a hot video card cooler is a judgement call, especially if there is more space elsewhere. The truth is most people probably don't use their 1x slots.

I found some ultra low profile pcie extensions (basically mining risers that use a USB3 cable) that allow me to relocate the cards elsewhere but still install them in slots that are under big GPU fans.

Those extensions sound interesting, can you share a link or model number?

There are M.2 extension cables, I have one that lets me put the M.2 in to the drive bay away from the motherboard. There's also M.2 bifurcation cables. And you can also put the M.2 on PCIe cards, with or without a PLX switch.

As mentioned, there is a wide variety of these available of different types. They were made popular and available enough by the mining boom that there are different styles (and different qualities).

This was the one I used: https://www.amazon.com/dp/B07N38Y799

The one I use, MSI X-570-A PRO [0], has space for a 2-slot GPU (are they 3 slot nowadays? I don’t know, I don’t do AI or shooter-games), and then 3 x1 and one x16 slot which seems pretty okay.

[0]: https://www.msi.com/Motherboard/X570-A-PRO/

> are they 3 slot nowadays?

In fact, some even clock in at 4.3 slots. https://www.asus.com/Motherboards-Components/Graphics-Cards/...

That card looks like it takes up 2 slots externally, but then has really tall fans on it.

The 2 or 3 top end Nvidia and AMD GPUs have been 3-slot for at least a couple years. I bought a Dell 6800xt on eBay that was notable for only taking up 2 slots.

Crazy. I only recently updated from an RX470 to an RX6600

Most consumers only have 1-2 NVMe drive and a GPU. So I presume OEMs don't want to have an M.2 slot buried under the GPU.

On AM4 ATX-boards slot 0 is often then primary M.2 slot. Slot 1 the GPU and slot 2 is either empty, or the CMOS battery, or like you suggested a secondary M.2.

So you're already down to a maximum of 5 PCIe slots.

They're doing it because it allows them to sell 'workstation' motherboards that do have decent slot spacing at ridiculous prices.

I had to resort to a mining rig style setup with 16 lane extenders to be able to properly utilize all the slots after running into the same issue.

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