Most casual crypto miners use a conventional motherboard, especially if they have a PC/case/power supply with sufficient PCIe slots for their GPUs. But when you get beyond 2-4 GPUs, you either need a rat’s nest of riser extenders, or maybe (just maybe) a dedicated mining motherboard.

I recently got a new-to-me mining motherboard, and found it painful to find some information and resources I needed. I’m aggregating this information in this post, and it will get updated as I get more relevant experience with the ONDA motherboard in question. If you have any info to share, feel free to comment below and I’ll update. (Last update 2021-03-14)

I’ve mined with an Octominer 8-slot motherboard for 3 years now. In addition to an onboard Celeron 3855U and a single DDR3 SODIMM RAM slot (max of 8GB), it has eight PCIe x16 slots, so you don’t need to use the common x1-to-x16 risers. It’s complicated in that you have to power the motherboard with a number of additional power connectors (in this case, 6-pin PCIe power leads from the power supply). But it sits flat on a custom frame I ordered in 2018, and it doesn’t have much that I don’t need (like lots of drive controllers, extra memory slots, audio, etc). And if you get a custom mining power supply (or breakout board) with only 6-pin connectors, you’re in good shape. 

Octominer has discontinued their 8-slot boards, and the boards may not support the latest GPUs on the market (much like the Ethos mining distro I used on it until this past week). I couldn’t get the board to boot with an AMD 5500XT GPU (Amazon, eBay) in the first slot, for example. So it’s chugging along with eight Sapphire Nitro+ RX580 8GB cards (Amazon, eBay), seven of which have been chugging for almost three years now.

While they still make custom boards, the only ways to get their products are either to find the rare used item on a marketplace, or to buy the one integrated rig they currently sell in quantities less than 10 (their x12 rig with everything but the GPUs, which runs almost $1,000 shipped to the US). 

Another company making custom boards is ONDA. You can usually find them on eBay or other marketplaces for a couple hundred dollars, with a range of slot support. I found a good deal on the B250 D8P-D4 recently, and since I wanted to aggregate a mess of old GPUs, it was an easy way to go.

The D8P-D4 has eight PCIe x16 slots (powered by 3 SATA and 3 Molex power drops on the edge of the board), and four x1 slots that can be used with risers, to bring you up to 12 GPUs if your GPU stock and power supply connections/wattage can handle them. 

One quirk to the x1 slots (seen near the SATA and mole connections below) is that longer GPUs will cover those up. I have ordered a pair of right angle x1 risers that I will try to connect under a full length GPU. I may also get around to trying a four-slot expander on one of those slots. If it works, you could conceivably get eight mainboard GPUs and sixteen riser GPUs on this board if you have enough power and GPUs. I don’t have enough spare GPUs to fully test this idea, but it might be fun to try. 

Unlike the Octominer B8PLUS, this Onda board has an open socket for the CPU (6th or 7th generation core/Pentium/Celeron) and in this model’s case it uses DDR4 SODIMM RAM (max of 8gb). The boot storage options are generous; you can boot from a USB flash drive, a SATA drive, or an mSATA drive. If you want to use the onboard HDMI port, your CPU will need to support the Intel integrated graphics. 

These tend to be cheaper than the B250 Mining Expert from ASUS, which has 19 slots but maxes at 13 without some outdated P104 mining-only GPUs. 

The build report (in progress)

I went with the B250-D8P-D4 as pictured in the previous section. 

I had a Pentium G4400 on hand from a previous procrastinated project, so I used it along with the stock Intel cooler, The prices seem to have gone up since I bought it ($120 or more, yow), but you can get them for about $60 used on eBay, and you should be able to use any 6th or 7th gen processor. The lower the TDP wattage, the better, and for mining you really only need 2 cores. 

The RAM is an 8GB DDR4-2400 SODIMM I picked up at Best Buy. You’re looking at about $40 for this part, and several reputable brands are available. You probably don’t need 2400 speed RAM, but whatever is available should be good.

I started with a PNY Geforce GTX 1080 8GB “blower model” since it was handy. After taking the photo I realized it would not fit with the power supply connected, so I switched to an MSI GTX 1060 6GB single-fan short card. You can find 1080 cards on eBay for under $500 (or over, depending on your timing) these days, and with the Ethlargement Pill software they can deliver around 35MH of Ethereum mining at ~100W.  

The Glyde 32GB USB 3.0 drive was already in hand, but you can use almost any USB drive with 16GB or more. I recommend using a new USB 3.0 drive with a plastic shell, even if your board only has USB 2.0, and I’d advise against the low profile ones like the Sandisk Ultra Fit for this use. I haven’t had a lot of these drives die, but I have had a couple of the low profile ones burn out on me. The SanDisk Ultra Flair is still a favorite ($7 for a 16GB unit) as are the Sandisk Ultra drives ($24 for three, various other combos available too). 

The power supply situation was complicated, in part because of a BIOS quirk below, but right now I have a EVGA 700 watt 80 Plus Gold power supply on the system. This will not power more than 3-5 GPUs, but I wanted to get through the build. 

The case is a $7 foldable and stackable shoe rack from Target, with a  layer of anti-static foam between the board and the shelf. 

The quirks it took way too much work to find

As widely used as this board is, you’d think there would be more condensed information on it. Alas, I had to go through a few bitcointalk threads, watch a few videos, and sacrifice a few chicken entrails to get the system going. 

Power quirks

These are easy, and if there were documentation available for the board they would’ve have been easier to figure out. 

There is a power jumper on the board, that if set will power the board up once the power supply is turned on, without need for a power switch. You can find it near the supplemental fan power connectors between the 24-pin power connector and the CR2032 CMOS battery. Mine was jumpered as shown when I got it, so it powered up automatically. 

If you do want a power switch, you can switch the jumper to normal behavior and connect a switch to the front panel connector. The middle pair of pins is the power switch header. 

Slot 1 nightmares

No, I’m not going to make you run a Celeron 300 in this board, although that was one of my first overclocking adventures with the ASUS P2B motherboard.

The problem that made me switch cables and go through three different power supplies was with PCIe x16 slot one. On a number of these boards, the first slot is configured differently from the others. In my case, slot one was set to Gen 2 speed, whereas the rest were “Auto.” After some research I found that a card in slot 2 should work even if slot 1 is misbehaving and keeping the board from booting.

I connected my monitor to the HDMI port and mashed the delete button on boot to get into BIOS, with my GPU in slot 2 and slot 1 empty. I changed slot one to “Auto” and it worked. You can also set your video priority here; I set the priority to iGPU (integrated graphics on the board/CPU). This has the additional benefit of not making the first GPU reduce aggressive clocking to support a video display. 

BIOS and driver updates

Onda has a website, in Chinese, where if you’re lucky you can find drivers and BIOS updates for your board. For the B250 D8P-D4, the relevant page seems to be this Magic Edition one. My board came with the V1.00 BIOS dated December 2017, so I am inclined to update it. 

It’s entirely conceivable that you won’t need this at all; if you run a mining distro, you don’t need drivers. And if you don’t need newer BIOS features, you can probably run with the original BIOS on the board.

But it appears that you may want an update to support 8th and 9th generation Intel Core processors and the newer GPUs. You would need an initially-supported CPU to update the BIOS, so start with 6th or 7th gen and then update BIOS if you want to upgrade to newer processors. As I hinted above, though, you probably don’t need more than a minimal 6th gen processor unless you plan to use CPU mining (i.e. for Monero).

I don’t have any 20-series cards, and I haven’t tried the 1660 SUPER or 30-series yet, but I’ll come back and update with whatever I can learn from the 16- and 30-series cards. 

Their website is dog-slow, non-https, and it took me several tries with wget to download the BIOS files and flashing instructions. And just because it wasn’t already hard enough, the files are RAR archives on an ftp server (so your browser may be confused on multiple fronts). But it seems the most reliable place to get these files if you do need them. 

Added: ONDA Bios Flash Guide in PDF form, unrared and translated from Chinese. In short, make a bootable drive and extract the BIOS rar file to it. Boot from that drive and follow the instructions. 

Update: I got a ME error on one of the updates, and a component not found on the other, so I’ll go back to the search for the appropriate BIOS for this board. 

Where do we go from here?

Funny you should ask. In April 2018, I ordered a 1200W HP Common Slot power supply (the kind you’d find in a rackmount server) and a breakout board to give me 16 6-pin PCIe drops for GPUs and the Octominer board. I promptly lost those, and finally rediscovered them this weekend. 

So my next goal is to get the power supply upgraded again, and plug a full complement of GPUs in (everything from 1060 to 3070 for now). 

Some useful links

These should be considered bookmarks, and not official endorsements in either direction. 

• Drone Fyre’s video on the Onda motherboard – this is how I figured out the power switch pin location. 
• A couple of bitcointalk threads (one, another, another, another, more to come?)