All X399 motherboards that support bifurcation with good iommu groups

Hi all, first time posting. I just got a smoking deal on a 1920X and am looking to upgrade my x79 machine. I run several VMs with hardware passed through so good iommu groups is a must. Also while not needed initially I like the idea of being able to expand the number of passed through devices with pcie bifurcation. Searching online I found several boards that offer this option for raid (as in x4x4x4x4) for nvme drives but have only seen confirmation on the two higher end asrock boards that offer x8x8 and x8x4x4 options. Does anyone know if the lower end asrock phantom board offers this option? Any other boards that would fit my needs? I am hoping as Threadripper 3 is announced and coming into black Friday and cyber Monday I might find a good deal on a x399 motherboard and the more boards I know that fit my needs the better my chances of finding a good deal. Thanks in advance for the help.

Really? I saw this post, the info is old and only at the end does someone say that due to new bios that the asrock boards I listed in my post now have this feature. I was asking if others also do and if the lower end asrock board does. Also asking about iommu groups with bifurcation which I could find nothing on. Now because of this one answer which gave me nothing I did not already see my thread is solved and locked?

use the search


I’ll reopen for you since you feel like your question isnt answered but I would ask that you also post any information you learn from outside the thread so that others may learn what you know too.

I can’t say if the Asrock Phantom 6 support bifurcation, but my Zenith Extreme does. And I’d guess Asus’s other two X399 boards does as well :slight_smile:
I don’t know how good the iommu groups are though, since I run W10 on my x399 system.
But the Phantom 6 is meant to be an entry level x399 board, so it might not be very feature rich, or have good iommu groups.

Thank you @Adubs for reopening the thread. I apologize for not listing the other threads I had read. I do not really post much on any forums and this is my first time here. Below are the 2 threads that I found the most useful info. I have also found bits and pieces in too many threads to list as a single comment here or there. Through all of my searching I really only found up to date info on the 2 asrock boards I mentioned in regards to them fitting my needs. Both boards are a bit outside my price range. This may change with TR3 and Black friday but I was hoping to find a board that fits my needs in the sub $300 range. In the thread linked below and by @kewldude007 I did find that the Asus Zenith also provided the bifurcation support I was looking for but one is priced higher than I would like but also could not find up to date info on iommu groups. The last bit I found they wer ok only but I know for many boards this has gotten better with bios updates. I would love to find out if the less expensive Asus boards have the bifurcation support as I have seen updated info that thier iommu groups look good. Also if someone could chime in on the low to mid-range MSI boards. Thanks all