Asus announces B250 Mining Expert motherboard with 3 24-pin connectors and 19 PCIe slots

This is something you don’t see everyday. I’m not that into the whole cryptocurrency thing but I saw this mentioned and looked into it. Turns out that it is (as far as I can tell) a real thing, even though it looks like something that would be announced as an April Fool’s joke.

Asus has just announced the B250 Mining Expert motherboard, a very peculiar motherboard aimed at the cryptocurrency mining market. What’s different about the motherboard? Take a gander…

The board sports 3 24-pin ATX power connectors, 3 Molex auxiliary power connectors and 19 PCI Express slots - 1 x16 slot and 18 x1 slots.

The B250-based LGA1151 board will reportedly have the slots split into three groups, each of which will have its own dedicated 24-pin ATX connector and Molex auxiliary connector. The POST UI (the screen shown at boot) will have a utility that shows the different PCIe connectors and their status - Green means a card is detected properly, red means there is an error and black means that no card is installed. The BIOS will also be tailored for the application this board is intended for - that is, mining.

Everything else about the board seems pretty sparse, it only has two RAM slots and a modest amount of I/O, but it doesn’t look unreasonable - you even get an Intel NIC, which is nice.

Pricing and availability have yet to be announced. As I said, I’m not a crypto miner at all, but this kind of board definitely scratches an itch in the back of my head. Depending on the price I kinda want to get one as a curiosity item. One thing I can see some crazy person doing is getting one of these and cramming a load of dirt-cheap Intel PRO/1000 ethernet NICs onto it with risers, in some kind of unholy abomination of a case with 19 brackets and using it as a router.

Let me know what you think of this. Even ignoring the doomed-to-die mining market, I do think that this could have some valid (albeit unusual) use cases elsewhere. I think it’s at least interesting. I’ll be waiting to see how those PCIe lanes are assigned, because it would kinda be a shame to have all of them go through the DMI…

At first this seemed kinda like rumor mill stuff because details about the board are limited and so far the most well known sources for this are wccftech and… yeah, I wasn’t enthusiastic about it either, but the sources seeeeeem to check out. If I’ve somehow got this wrong, let me know.

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If there is a demand for it, it shall be made.


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The 3x 24 pin is a very odd approach, I’m guessing its so you don’t need to jumper the secondary supplies. However it seems strange to me it only has one 4+4pin, leaving the other two hanging uselessly, then draws on three moles (yuk) for secondary power.

Also those molex are on 132w max (11A @ 12v) each, while PCIe graphics cards spec allows 75w per device to be drawn… despite this board only having connectors for 20w per device. Thats not a good sign for this being real… especially when you add to the fact existing mining boards all have the PCIe slots in a line with the standard ~18mm widths to follow the spec, not in multiple banks across the boards width. The intel consumer socket is also pretty PCIe lane limited, with just 16x PCIe3.0 and 8x PCIe2.0… so 19 slots (even at 1x) seems a very odd number (same goes for ryzen, dispite 30 lanes internal only 24 pass through AM4 sockets). You’d think they’d either have 16 or 24 slots total, or more logically use a server socket… which would also allow pairing with a very low power CPU and give plenty of lanes.

Worse the intel B250 chipset limits PCIe lanes further… with only 16 lanes possible, vs the 24 on h or z series board… making it a bad choice for mining and unable to support that many slots… so sadly I must say I can’t belive such a report as it’d require lane devision which will cost more than just a H chipset, which would allow all the 1x slots a lane and a 4x lanes on the 16x slot. However unlike a server board it still won’t doesn’t support intel manageability or other useful features for non-desktop application.

Like you I think the mining on graphics cards market is doomed to be short lived, as soon as somebody makes new dedicated hardware for any given algorithm it’ll win out, however I’m super interested in these boards for other applications, like GPU based compute to silly tasks like running a dozen 4x Nics ect.


I’m not that much into the spec, but you mean those aweful Molex 4pin things only right? In Addition to that the ATX plugs also supply 6 cards each, not sure if that is sufficient. But then again I guess Asus has a basic idea of what they’re doing. I don’t think they’d risk anything in this market.

not true, Biostar announced their version with 13 Slots a month ago that has the same layout. People use risers anyway, so it doesn’t matter where they are located. They could be standing upside down for all they care… and (I’m not a miner, just read on it so please correct me if I’m wrong) those risers are USB powered too.

aren’t most of the altcoins (at least ethereum?) designed around not being suited for ASIC?

19 GPU folding rig? mh… not sure if that would even work :smiley:

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This is true at the moment, but it looks as though this motherboard’s release is prompting a driver update from AMD (and likely Nvidia) that allows you to connect up to 19 graphics cards to a given computer. At the moment iirc it’s limited to around 11 (edit: It’s 8)

As far as I read (not sure if this is still true) both drivers only recognize 8 cards each, so it would be a total of 16. Not quite sure how stable this is though (electricity issues aside).

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Yeah, the horrible molex p4 inline connectors… offically they support 11amp at the connector, so you can buy cables that are rated for that, although honestly I wouldn’t put more tthan 5amp through most on the market due to their wiregauge (but then again most p4 input HDD’s or floppy’s only draw 2amp or so, and fans even less).

The 24 pin connectors DO carry power, but not as much as you’d think as its mostly other voltages, the 24 being an extension of the 20 pin standard to add another 4 pin square 12v power connector (2x 12v and 2x ground) as PC’s swapped from running the CPU’s VRM’s off 3.3v or 5v to the more modern 12v, and started getting graphics (the board power also went from one square 12v 4 pin, to a 4+4 as they added the graphics extension, allowing graphics adaptors to draw up to 75w instead of just 25w). So I’d wager the 2 spare 24pins could add no more than 75w each, while each slot wants 25w or more to meet spec. Although worth noting most PCIe riser ribbons grab power externally rather than from the slot, so while it totally breaks the standards they just may not expect you do be drawing current via the 18 PCIe 1x slots at all.

Didn’t see the biostar, but I’ll take your word for it.

Yes, but when you give people a harder problem, but basically pay they money for solving it quicker than anyone else, it normally doesn’t mean they never find another way. Bitcoin didn’t used to work on Asic miners, then they made better miners. Folding at home used to only work on CPU’s, now it works on GPU’s. People build a better algorithm, or better hardware.

19 GPU’s impossible? Well yes, like I said, especially because the B series chipset doesn’t even allow 19 lanes, only the 16 PCIe3.0, so I suspect this board is only a rumor.

On the other hand if it had no 16x slot, and only 16 PCIe 1x slots in a 4x4 grid on a mATX board. Then just used a 2 pin start output to 20 pin female cable to allow you to add PSU’s, rather than the highly space consuming multiple 24pin sockets. Also had a reasonable 12v input solution like 4x 8pin PCIe power connectors (with 8 pins plugged in 150w each, with 6pin connectors plugged in 75w each, and critically the same standard as you’l be running to compute or graphics cards), it’d still be extremely cool product that I’d pay up to ~$250 for. Although a server chipset to support the sorts of features involved in high availability headless running would make even more sense, because running a GUI and integrated graphics is both a waste of performance and not the fastest\easiest way to maintain a bunch of systems. Sadly by this point it sounds nothing like the rumored product, so I’ll dream on…

The asus board is not a rumor, it was an official announcement by Asus. Still wondering how they’re working with the lanes though. As I understand most are routed through the PCH, the rest directly to CPU probably.

There are also a few more pretty pictures:


Well then, the rabbit hole gets deeper…

No comment anywhere in the write-up or slides about how it gets extra PCIe lanes and no sign of another chip (although it could just be under the chipset heatspreader).

Also they say in one slide that you can’t use more than 8 of each NVIDIA and AMD GPU’s in multiprocessing mode, stating directly you can run up to 16x graphics cards (despite having 18 of the 1x ports), then in another slide show a table that suggests there may be a driver to use up to 11 AMD cards… so either way your officially recommend using a mix of AMD or NVIDIA. Annoyingly if they just had a 2nd NIC you could just run 2 VM’s with a NIC and 8 cards passed through to each, because I’d assume miners are going to have a preferred card for a workload rather than desiring a mix.

Also turns out I was wrong about my estimation of the 24pin, one of the +4 is 3.3v, although it can support 144w according to Intels revised specs. So there is 46w available to the PCIe 1x slots (as long as you don’t use the 16x in group 1, then that group is only 33.5w. This is then technically within spec if you do not use them for graphics cards, so if mining you still better still have aux power to your 16x adapter risers or risk problems.

Supposedly there will be a driver update from AMD allowing all 19 slots to be used for GPUs. Makes sense since there have been very few motherboards historically that have 8 PCIe slots, let alone 19.

screenshot from one of the articles:


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lol at least they provided audio, else I’d say this was a travesty



Lol yeah.

Its got a realtek ALC887, so its a average 8 channel device, probably cheaper to copy paste an existing layout than finding a new chip thats more basic I’d wager. But its funnier because it has that “audio separation line” drawn on the PCB still, despite nobody caring.

Its even odder when you think that the only video out is HDMI, so if you really wanted audio you could get the digital signal from that cord and play it via the DAC on your monitor or KVM anyway, so there is no good reason to have any analog audio signal handling on the Mobo if your using its only display output. A small 8 segment display or literally even a big buzzer so that the machine can warn you if something is wrong would make more sense.

One of the slides from the German website had a breakdown of how the cards can be used. Nvidia are limited to 8 and right now AMD are also limited to 8 but apparently the slide says there is a driver to allow 11 to be used. So 11 and 8 is 19.


Kemoka73 later added that they also said in one of the AMD planned drivers to let you use all 19 slots.


Whoops missed some of that. Sorry, jumped the gun a little.

No worries, sounds like something I’d do =P

Will this lead to a market flooded with motherboards as miners upgrade to a giant system with just one motherboard?

I’d be nice, but no. These 19 slot boards have a lower cost to buy per ammount of GPU horsepower, the power to run one idling pentium and single DIMM of ram won’t pay off a swap during the year or two of the mining craze remaining on GPU’s, so few miners will consolidate by getting rid of working boards.

Yet it really would be nice as traditionally motherboards die long before CPU’s, so while new most people pay more for CPU than Mobo by a long way, its often hard or expensive to find motherboards for older sockets. Having said that, I doubt it’ll make much difference, miners have a huge impact on GPU prices because they want the big FLOP count cards that are actually even a very small amount of even the gaming market, which is itself only a portion of all PC users who’d use basic consumer socket motherboards. Not to mention they have like 6-7 cards per board, so the flooding effect would be 6x less even if it only reached the same limited demographic.