Nvidia RTX 30xx

[iamaibeta]

No. I mean MBs with 4 PCIe (at least) 8x slots with at least 2 that are at least 2 slots apart. For example, if I get a 7 PCI-E slot X299 board, I could put 3 cards on Top, 4th, and then 7th, and have quite a bit of clearance between the cards. One of the cards will probably be confined to PCI-e x 8 but I don't care.

The options for MBs like that are pretty thin on the AMD side. Something like X299 MB with 7 PCI-E slots, 1600w PSU, 3x3090 (prefer 3080ti, but it will depend on availability) I think is the best I can do without resorting to watercooling, risers, or some other very customized solution.

[RobertJasiek]

When you write 2 slots apart, you seem to mean 2 slots in between, so I call that 3 slots apart, which means 2.08cm free space between two cards each being 2 slots thick.

Yes, suitable mainboards are scarce and somewhat expensive.

[John Fairbairn]

When you write 2 slots apart, you seem to mean 2 slots in between, so I call that 3 slots apart,

As a native speaker, I call it 2 slots apart. In go we likewise have one-space jump, one-space pincer, two-space extension, etc where the numeral indicates the number of empty points between the two boundary posts. I haven't thought about it before, but that seems, off the top of my head, common to all the languages I know.

Is German really different in that regard? Or is it just your personal foible?

If the boundary posts are together. that is 0 slots apart. You can't possibly say that is 1 slot apart. The next step up is surely 1 slot apart, and so on ad infinitum.

[RobertJasiek]

If we only have the PCIe slots (without cards in them), there is a gap even between adjacent slots. The most useful measure of that gap is between centers of slots. From a slot to itself is 0. From a slot to an adjacent (not omitted) slot is 1 (multiply by 2.08cm if you like).

A card being said to be 2 slots thick has 2 (or 2 * 2.08cm).

If you put two cards each 2 slots thick into slots 1 and 3 (slot 2 is skipped), ideally they attach each other so the gap between the cards is 0 while their slot positions are 2 apart.

If you put two such cards in slots 1 and 4 (slots 2 and 3 skipped in ordinary ATX layout), the gap between the cards is 1 while their slot positions are 3 apart.

It is not the one-space jump gap counting but a measurement of the grid distance of its stones' centers.

[Harleqin]

The usage of »n spaces apart« does seem to differ even within native German and English speakers. I am more used to the definition that 1 and 2 are 1 apart, and I distinctly remember very explicit (because it is not self-explanatory) explanations that a »three space extension« in japanese usage is meant to be »three free grid points in the space between«.

One may think that these different views are equivalent, but I personally find it very useful when such numbers add up. So, if I have two things that are 2 units apart, and another thing in the same direction that is another 3 units from the second, then it should be 5 units from the first.

However, if you do two »ikken tobi« in a row, then if you take away the middle one, you end up not with a »niken tobi« (1 + 1 = 2), but with a »sanken tobi«, which, when seen from this perspective might as well be a 散見跳び.

Anyway, in Go, it seems to be this way, but in engineering, it is that way.

[Bill Spight]

FWIW, to me apart means to the side, not in between. So slots 1 and 2 are one slot apart, while slots 1 and 3 have one slot in between, and are two slots apart.

Now, if the distance is measured differently, the two converge. Seats that are 2 metres apart have 2 metres in between them.

[iamaibeta]

For what it's worth, I tried the config with 3090s. They are so thick even with two slots in between, there is very little clearance and they still overheated. EVGA and Zotac 3080s also overheated on top. The founder's edition 3080 was the only one that didn't throttle a lot when put on top but even then it was running pretty close to throttling with fans blasting at 95%. I could maybe undervolt it and get 90% of the performance while keeping the card reasonably cool but I am just not going to do that.

I am at the point I think I have to get risers/rack/watercooling. Gonna have to see if I could convince my firm to subsidize this expense.

[RobertJasiek]

Thank you for your report! Although it might have to do with Lian Li's case, we are warned that a closed case with 2 thick high-TDP aircooled cards at constant workload can easily overheat even in winter.

[John Fairbairn]

FWIW, to me apart means to the side, not in between. So slots 1 and 2 are one slot apart, while slots 1 and 3 have one slot in between, and are two slots apart.

For the last case I would say "one slot away".

Now, if the distance is measured differently, the two converge. Seats that are 2 metres apart have 2 metres in between them.

And for that I would say "two yards apart"

[RobertJasiek]

RTX 3060 comes with BIOS (and driver) restrictions for (Ethereum) mining, whose hashrate shall fall by up to 50%. Possibly successors of RTX 3060 TI, 3070, 3070 TI, 3080 and 3090 might also get such a restriction. Now I wonder whether that only affects mining algorithms or whether other high workloads, such as go AI, will also be affected. Is the future good or bad?!

[RobertJasiek]

This video by JimRPG comes to similar conclusions about cards becoming hot especially at their VRAMs:

https://m.youtube.com/watch?v=1ywKemBUnuk

"Don't Buy a RTX 3090 for Mining... or Gaming. GDDR6X Temperatures more than 100 deg Celsius."

[KayBur]

This video by JimRPG comes to similar conclusions about cards becoming hot especially at their VRAMs:

https://m.youtube.com/watch?v=1ywKemBUnuk

"Don't Buy a RTX 3090 for Mining... or Gaming. GDDR6X Temperatures more than 100 deg Celsius."

Hmm, my brother has such a video card, there is no overheating. He plays fairly resource-intensive computer games and does not experience performance problems.

[iamaibeta]

I went ahead and tested 1x3090 + 3x3080 on a test bench (aka motherboard's box and my desk). I had to use risers to get them to fit on an X299 board. They were all 3 PCI slots tall and just didn't physically fit on the board without the risers.

The setup just wasn't stable with a 1600w PSU. It would go for a few hours then just reboot randomly. I probably could fix it by limiting the power draw on the cards but otherwise I probably need to go to 2000w psu and I am concerned even 2000w would have issues with 4x overclocked 3090s. I couldn't even find 2000w PSUs in stock. I am guessing miners got them.

All in all, 4x3090 dream is just getting more expensive and more troublesome than I expected. The 30xx series cards just are so clearly not designed to be stacked, I feel kind of defeated. I did find that some manufacturers (Asus included) make "blower" versions of 3090 that are shorter and clearly designed for stacking. But I literally can't even find them listed anywhere except on specialist system builders (e.g. Puget)

Water cooling is starting to sound pretty good now.

[RobertJasiek]

Are you in the hardware business so that you have access to some cards?

Top PSUs suffer from miners, transport delays and ressource / component shortages.

[iamaibeta]

I got some early and just kept picking them up when I found them. One of the 3080s is from stockx.com for $1200+taxes.