TLDR,. I’m looking for a 8th gen Intel motherboard that supports 4 x 4 bifurcation. I need a full size ATX board with 6 pcie slots that I can then carve up.
More generally, can anyone link some pages that provide information or ideally lists, what motherboards support pcie bifurcation?
I need to run too many x1 cards and I’d rather not run 2 systems if I can help it.
With that much need you probably just need to go X299/ X399 / sTR40.
Do you have any specifics on what exactly you are trying to do other then carve up the lanes.
It’s for mining risers. I didn’t immediately want to send people into rage mode.
I tried using 2 different m.2 to PCIE adapter first but my board wouldn’t post with it installed. I have a simple PCIE card that should split the signal between 4 devices but that only works if the board will support it. I haven’t seen anything with a PLX chip on it.
I don’t know that I want the idle power draw that a HEDT platform will give me.
All solar here. Fuck Duke Power!
Why not just use the USB to pcie adatpers?
Trying that many PCIe devices (6), would need you doing some HEDT series board [ Intel* X99, X299 / AMD sTR4, TRx4] for outright assurance in physical slots. Also then board producer dependent, on how easy to engage the bifurcation [and how much divvying allowed, in each slot].
*Do keep tabs on Intel CPU choice, as some SKUs reduce total PCIe lanes
He probably doesnt need a ton of bandwidth to each gpu as its mining so not heavy transfer just a lot of crunching of data. (pretty sure thats how it works)
I do use pcie to USB. Like this:
6 Pack VER009S PCI-E Riser Card PCIe 1x to 16x USB 3.0 Data Cable Graphic Extension for Bitcoin GPU Mining Powered Riser Adapter Card https://www.amazon.com/dp/B091DMQVHC/ref=cm_sw_r_apan_glt_fabc_JJFBJ4S6W0WJGACJNZR1
There are some add in cards that split x1 into 4 USB female connections, but those will require the bifurcation support. I’ve tried them without it and my board won’t boot with 2 risers connected to them.
@GoldenAngel1997 thanks! I was aware of that and have been looking at board manuals to try and figure this out. It’s been very tedious.
@mutation666 that’s correct. It’s not bandwidth intensive at all. What I’m running is all at pcie gen 1 speeds.
I dont think biforcation is something supported on that old of product. I could be wrong, but thinking about it some more i feel like biforcation was only like a 2xxx/3xxx ryzen stuff first then added to other stuff later.
https://www.asus.com/us/support/FAQ/1037507
Probably any Z590, Z490, Z390 and Z370 board
That URL has a ton of good data for ASUS boards
I know Wendell has reviewed quite a few boards, over the years. Could be a good start point
@mutation666 thanks for the chart and link. I read a few manuals from the Asus z370/90 boards and saw only a brief mention of bifurcation for nvme ssds, as your chart showed. I’ll have to check my board to see if toggling that helps me.
You may be right that I need to be looking toward more modern platforms. Ill have to look at the 10/11th gen processors and boards to see what is available and their mother oard compatibility.
Nvme Devices are Nvme devices doesnt matter
When I was trying to solve my NVME issues one of the things I kept seeing was people using m.2 slots to connect risers, think some loon had 10 GPU’s on a single x570 board that way.
You won’t need bifurcation if you have at least 6 slots which should be doable on ATX boards
Your main problem will be running out of bar space, enable above 4G decoding switch to UEFI only mode, disable haswell and under boards will struggle with 16Gb of bar space and it rounds up to the next double so if you have a 6Gb card it’s 8Gb of bar space
Get a board and CPU that supports resizable bar space or SAM, other than that how much bar space a board can handle is even harder to find out than if it has bifurcation or not
@mutation666 fair enough! 
@penrowe I have 6 now, ATX boards ftw! I just want 2 more to fill out my mining frames. Those dedicated mining boards are going for $300+ now, when available.
@GigaBusterEXE I’m powering everything with pcie, no SATA for me. Being very conservative on my power draw per PSU. Got 4g decoding on. Oldest board I have is Intel 8th gen.
I’ll look into Sam/bar support. I need to read more on it. Thank you all for the good information!!
While I dont support crypto(in its current form the concept is fine), If you want to do it I don’t care its up to you. GL with the build. Post some updates / pictures
Still struggling with bifurcation, but here is a pic of my Sapphire 6600 XT rig
Now to do something about the heat!
Have you been getting tese for MSRP?
When I couldn’t ever find a non scalped 3080 I gave in to my more base desires and bought a 3090 instead. It’s paid for itself by now but even if I’d gone all in on mining I can’t imagine I’d spend 80-100% over MSRP to get set up.
When I got these I was paying $525. Not great but now the best I can find is $599.
To me what’s more important is the hashrate/watt efficiency. Even when crypto values go down you can leave them running longest before they’re costing you money.
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