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Comment by walrus01 | Hacker News Reader

for anyone that has a very new motherboard/chipset with proper PCI-E 4.0 support, and wants to add a lot of NVME M.2 format storage (in addition to the on-motherboard M.2 slots), take a look at this:

https://www.asus.com/ca-en/Motherboard-Accessories/HYPER-M-2...

It costs about $70 USD.

In a single socket ryzen zen3 workstation you'd typically be able to use one of these. One PCI-E 4.0 x16 slot for your video card, one slot for this.

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Just curious for my own sake—is there a board out there with two electrically PCIe 4.0 x16 slots? I was under the impression that Ryzen Zen 3 has just 24 PCIe lanes, and usually four are split out for the chipset, so how could you run both your x16 video card and x16 M.2 carrier simultaneously without linking one at a lower rate?

Yes yes yes this you're absolutely right. Virtually every motherboards has two "x16" slots but only the first x16 is actually x16, one on the far side from CPU is electrically just x4 and is mutually exclusive with first M.2 slot. Unless you're building Threadripper/EPYC or Xeon HEDT/server. I didn't realize any of that and am enjoying free salt.

It's not quite that bad. Lots of motherboards connect the primary x16 to two slots, which can either be used as x16+empty or x8+x8. And x8 is quite a lot at 4.0 speeds.

Threadripper has 64 lanes (except 3990x, which has 88), and I think most motherboard for it have 2 PCIe 4.0 x16 slots. EPYC has even more lanes.

The chipset's only fed by 4 lanes, so while it technically could be fully connected to a second x16 slot it would be kind of crazy for a motherboard maker to actually do that since the chipset only supplies 16 lanes total.

Realistically you need to give this card your main slot and your GPU can get an x4 connection and lose a few fps.

The Hyper M.2 requires a motherboard that supports PCIe bifurcation. If not, you'll need a card with a built-in switch like an Ableconn PEXM2.

Fortunately, AMD seems willing to enable bifurcation on all their desktop platforms instead of using Intel's strategy of treating it as a product segmentation thing. Quad M.2 risers work in both my B550 and X570 system.

Artificial "product segmentation" is such nonsense. If you're able to put in the extra effort of disabling features that you just get for free otherwise, and make more profit by doing so that's just a sign that the market you're operating in is severely lacking in competition. It's good to finally see AMD giving Intel a run for their money.

Eh, it's like how non-K intel processors technically can be overclocked* in that less features can mean you get the same CPU but cheaper.

*: I know there are other reasons for non-K processors (binning might actually mean your non-K CPU can't overclock), but it's largely just a way to move more product and sell at a lower price point to those who can't afford unlocked or otherwise wouldn't have overclocked.

If Intel can disable a feature and sell something at a lower price, then they could also sell the same thing at that lowered price without the feature disabled. The only reason they don't is because they exist in a patent encumbered, (very) competition light environment.

(Binning because of imperfect production yields is different though and I don't have a problem with that. It's hard to tell how much of the K/non-K split is legitimate binning, and how much is just a bool in the microcode).

Didnt stop AMD from disabling PCI Express Resizable BAR support, hidden behind AMD marketing wank "smart access memory (TM)" name, on older "chipsets" despite both memory and PCIE controllers being build INTO THE CPU ....

https://www.amd.com/en/technologies/smart-access-memory

Or that time x470 was going to support PCIE 4, but then it was made x570 exclusive

Resizable BAR support was added in the latest BIOS update of my B450 motherboard (that also added Zen 3 compatibility).

I had no idea this kind of riser was possible. That solves a problem I have at the moment.

I'm concerned about heat if that little fan goes. I know the storage throttles, but I would imagine 90C+ flash memory is not good for it's long term durability.

I'd like to see a complete fin heatsink that benefits from case flow.

I think the fan and enclosure are a bad idea personally, you'd achieve better cooling on the M.2 cards by leaving it off and having a case that has sufficient airflow front to rear in it. And possibly gluing your own small aluminum heatsinks onto the M.2 cards (which are cheap and easy to do), if they don't come with their own heatsinks.

It depends. Because NAND flash storage relies on electron tunneling, you actually need high temps for the mechanism to work well. Too much cooling and you'd be increasing the wear levels prematurely.

Not sure if this thing is smart enough to know when to kick the fans on and when to keep the temps "high". That is something worth noting though.

There was even technology announced for self healing NAND flash - drives that could cook itself to 800C to heal worn out cells. Never materialized tho :(

https://www.extremetech.com/computing/142096-self-healing-se...

https://hardware.slashdot.org/story/12/12/02/2222235/self-he...

https://ieeexplore.ieee.org/document/7524803

https://www.eeweb.com/industrial-temperature-and-nand-flash-...

I found this here that says lower temperatures are better for storage but higher temperatures are better for writes. I'm not sure how accurate that all is though

Wait! There is commodity hardware that relies on electron tunneling?!

Yep. Welcome to the future!

https://en.wikipedia.org/wiki/Field_electron_emission#Fowler...

Slightly more specific: https://en.wikipedia.org/wiki/Flash_memory?wprov=sfti1

Go to "Writing and erasing". It links to: https://en.wikipedia.org/wiki/Tunnel_injection?wprov=sfti1

The enclosure itself is a giant heatsink [1] so I imagine it is fine if you only run 2 NVMe SSDs in this with a bit of case flow.

[1] https://youtu.be/ApXsJkUKDGI?t=341

Not really. Each card would only get 8 lanes. Then no more then two NVME drives will work in the storage card and that only if the board has bifurcation support.

For PCI-E 3.0 i can recommend a card with a Broadcom PEX 8724 controller. Works well with 4 drives and is not much more expensive. The fan is horrible: https://www.aliexpress.com/item/1005001782779648.html

Not sure why this is downvoted. Almost all (if not all?) consumer motherboards will drop the 2 x16 slots to x8 mode if you insert anything in the second slot. So using a PCIe riser for NVME SSDs means your GPU will get less bandwidth. This may or may not be noticeable, if you are running PCIe 4 the x8 will definitely not bottleneck the GPU, but x8 PICe 3 lanes probably will, especially for cards with less VRAM.

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