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Comment by jitl | Hacker News Reader

Most motherboards I’ve looked at in the last 4 years have at least a couple M.2 slots. I built a new small form factor PC in 2020 w/ AMD Zen 3 in a DAN A4 case, and haven’t filled up the 2tb of M.2 Samsung storage in my single populated slot. I’m curious what kind of price point this feature makes sense for. Old motherboard without M.2 but new enough to support bifurcation for the PCI 5? Doesn’t seem like a big window for to me, but I’m probably missing something.

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A 2TB drive is what, 8-10 AAA games? More drive slots is always better.

Not if you can't use them. The problem with modern PCs is lack of pcie lanes. Unless you go with Threadripper you pretty much get one GPU, two m.2 drives and one pci slot. After that decisions have to be made on what gets disabled.

I'm no expert here, but isn't this the number of lanes used at one time? If my understanding is correct, then generally more slots should still be better. Sure, maybe you can't write to 30 drives at the same time but who's actually doing that? You're probably reading from no more than 2 drives __at a time__. So 4 lanes per M.2 + a graphics card at 16 lanes gives you 22. Your $600 AMD Ryzen 9 7950X has 28 lanes but 22 are usable. So that of course doesn't leave you with extra lanes for other things, but that's not high end. Threadrippers have >80 lanes so...

Am I misunderstanding something?

Support for PCI-E bifurcation on consumer motherboards was really good for a while when PCI-E 4.0 first came out, however it has since regressed again.

Not many motherboards in the latest gen can do a proper x8+x4+x4 split. They may claim to support it but you run into weird issues has to spend weeks waiting for a bios fix. Or sometimes the support might be there but it is so poorly explained in the manual that I had to actually test it on hand to make sure that I was reading it correctly.

To be fair, HEDT motherboards are not immune to this type of stupidity. However they do manage to get over these issues with the sheer number of lanes.

AMD's mainstream desktop platform effectively has four more PCIe lanes coming out of the CPU socket than Intel's mainstream desktop platform. Both then have a variable number of PCIe lanes fanned out from the chipset and sharing that chipset's uplink to the CPU. (Intel has a range of chipsets with different number of lanes enabled, and AMD's more expensive chipset solution is to daisy-chain a second chipset).

Sort of, there's also dedicated PCIe lanes (on AMD) or DMI lanes (on Intel) to the southbridge which fans them out to additional lanes for devices.

Seriously - who’s installing even 5 of those big games concurrently? I uninstall games pretty readily.

>who’s installing even 5 of those big games concurrently?

Gamers?

Depends on your internet connection. If you have gigabit fibre to the home, downloading a big AAA game isn't a big deal. If you're on a 30 Mbit cable connection, the delay between starting a download and playing a game is pretty long, so it's nice to be able to keep them on your local storage.

Your approach is atypical. Most don’t uninstall unless they’re upset with the game or space is running low.

With ISP data caps, redownloading them isn't free.

I don't understand data caps, is it a US thing?

It's a US thing, but it depends on your ISP. I have Spectrum, which doesn't have data caps, but Xfinity/Comcast caps you at 1.2TB/month, charging $10/50GB after that, or am alternativse, more expensive unlimited plan.

~50GB per game, so 40.

Recently it’s gotten worse than that, a 2TB disk has about 1,820GB of usable space

STAR WARS Jedi: Survivor starts at 155 GB but you need over 100GB on top of that for patches etc, don’t be surprised if your game folder hits 240 GB.

Baldur's Gate 3: lists 150 GB as minimum disk space required.

Cyberpunk 2077 starts at 70 GB but the expansion is supposedly another 32GB and counting.

Alan Wake 2: 90GB disk space

Going forward it’s only getting worse.

I recently installed Starfield and it's over 100GB. I'm not a big gamer, but I understand this is becoming increasingly common.

https://store.steampowered.com/app/1716740/Starfield/

Or 1 or 2 electron apps

wait, i thought we were talking about SSDs not RAM /s

Most motherboards have a single dedicated M.2 from the CPU, a second one shared with the PCIe 4x slot and some have a third one from the chipset, usually slower. If you want a 10 Gbps NIC in your PCI 4x slot, second M.2 is gone and, if you don't have a third one from the chipset then you are limited to a single M.2 and Asus gives you the second one. That's exactly my case with one of the desktops, I would pay $10-20 extra for that extra M.2.

Maybe if you’re looking at bargain basement boards, but most boards? No way.

MSI B550 Mortar, mid-tier AM4 motherboard: 2 M.2 slots, one shared with the PCIe 4x slot. All the boards in that range are configured the same way.

The article said it's for small form factor PCs - were the motherboards you were looking at designed for microatx or something similar?

My build is Mini ITX

Will be pretty dope for eGPUs over thunderbolt

That won’t work electrically, and it’d have crippling performance problems if it did. Thunderbolt is not that much bandwidth compared to gen4 x16 pcie, and there are already latency problems to boot.

Do any Thunderbolt eGPU enclosures provide a full x16 slot? The M.2 slot on this card won't work if the card is installed in a slot that only has x4 or x8 lanes provided.

No they do not, however, it has never been totally clear to me if the TB-Pcie bridge they use in eGPU enclosures provides x16 slot and the "x4 equivalent speed" bottleneck is in the TB link, or if it's physically an x16 slot that only has x4 wired up. If it's the former, it will work.

Looking through the specs on ark.intel.com, the Thunderbolt controllers that specify PCIe lane counts say at best they support one x4 or four x1 links, so any eGPU enclosure using those would need to connect the Thunderbolt controller to a large and expensive PCIe packet switch in order to provide more than four lanes of any speed to a GPU.

Ah, it won't work then. Oh well.

Wow how do you keep your storage so low? I’m always running out of m.2 and SATA ports.

2tb is more than enough to hold the games I’m currently playing. When I run out of space going to install a new game, there’s always a few hundred GB of games I don’t play anymore that I can delete. I don’t hoard any kinds of media or personal data on the Windows machine.

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