Mini PC & Server

Does the Minisforum MS-01 support bifurcation with the PCI-e slot?

Does the Minisforum MS-01 support bifurcation with the PCI-e slot? Find out if you can split a single PCI-e connection to connect multiple devices.

Highlights

  • It would be great if this might be a BIOS update from the Minisforum side of things, but there may be some hardware limitations underneath that prevent bifurcation in general, which I am wondering due to the loss of half of the system memory when adding the card.
  • I have used the technology many times in the past with my Supermicro servers, especially for installing an NVMe add-on card to add (2) additional NVMe drives into the Supermicro server, in addition to the (1) NVMe slot included on the motherboard.
  • Even though I didn’t see the option in the BIOS I threw in a Supermicro dual-NVMe card I had with (2) NVMe drives.

Unfortunately, it doesn’t look like it does in the BIOS. There is no option to set bifurcation on the slot. It seems there is only the option to enable or disable the slot. Let’s take a look at what was discovered in my testing with the Minisforum MS-01.

What is Bifurcation?

You may wonder what this long word “bifurcation” actually is. In simple terms, bifurcation is the process of splitting a single PCI-e connection into multiple lanes to connect multiple devices instead of a single device.

I have used the technology many times in the past with my Supermicro servers, especially for installing an NVMe add-on card to add (2) additional NVMe drives into the Supermicro server, in addition to the (1) NVMe slot included on the motherboard.

In that case, a single x16 slot can be bifurcated into (4) x4 slots. There are usually other settings as well. On my Supermicros, they can also split it into (2) x8 slots. Most motherboards that support it allow you to customize how these can be split into different lanes and their configuration.

Testing with the Minisforum MS-01

I was able to do some more testing to confirm or deny bifurcation. Even though I didn’t see the option in the BIOS I threw in a Supermicro dual-NVMe card I had with (2) NVMe drives.

The minisforum ms 01
The minisforum ms 01

One of the first non-optimal things I saw was I lost 32 GB of RAM in the process of adding the card with 2 NVMe drives.

Only getting half the amount of ram when plugging in addon card
Only getting half the amount of ram when plugging in addon card

When I booted into vSphere, I went to the storage devices screen, and it recognized the first NVMe drive in the card but not the other.

Not all nvme drives are recognized with on the esxi host
Not all nvme drives are recognized with on the esxi host

Also, I scanned for new storage devices and none were found.

No storage devices found in vmware esxi
No storage devices found in vmware esxi

So, I just wanted to make sure that even though there wasn’t any bifurcation showing the BIOS, there wasn’t any magic happening behind the scenes, and it would just work, but apparently, there isn’t.

After removing the card and booting the MS-01, I saw the full 64 GB of memory again.

After removing the add on card from the minisforum ms 01
After removing the add on card from the minisforum ms 01

It would be great if this might be a BIOS update from the Minisforum side of things, but there may be some hardware limitations underneath that prevent bifurcation in general, which I am wondering due to the loss of half of the system memory when adding the card.

I checked, and the MS-01 does not currently have any BIOS downloads available.

Firmware downloads not yet available
Firmware downloads not yet available

Please post here if you know of any tricks or hacks you have found to make this work.

Comments from Minisforum employee on Bifurcation and RAM issue

In the VHT forums (now moved to Discord), a Minisforum employee noted that:: “Because of Intel’s CPU hardware limit, There is not possabile bifurcation on Alderlake-H platform CPU.(on that PCIE slot).”

What about the RAM issue?

“we found a bug for RAM identify. There have a SMBUS compatible issue between RAM and PCIE slot. Please follow the link from Wikipedia: https://en.wikipedia.org/wiki/PCI_Express. And use tape to shield smbus on smbus. To solve ram identify problem. And use tape to shield smbus on smbus. To solve ram identify problem.

MS-01 previous version hardware, share SMBUS between RAM and PCIE slot.

(RAM identify uses SMBUS)

For PCIE cards that have SMBUS, it may cause a conflict between RAM and the PCIE card. Further, one less memory, or even both memory, cannot be identified and cannot boot up.

To solve this problem, if you have an SMBUS PCIE card, just use Tape to shield the SMBUS pins before insertion.

These are SMBUS function pins,

And there is an example of how to do it.”

Example of pins for bifurcation
Example of pins for bifurcation

The below shows tape covering the needed PINs for solving the issue of RAM identify.

Using tape to cover pins
Using tape to cover pins

Also, according to the comment of the employee at Minisforum, it sounds like they are planning a new batch that won’t have the problem with the RAM identification as the current batch has.

What to do next?

If you are looking at a use case with the Minisforum MS-01 that involves or has a requirement for bifurcation, it looks like the current model is not capable due to Intel limitations. Also, in regards to plugging in cards into the PCI-e slot and noticing half your RAM is missing, Minisforum knows about this issue. As shown, there is a rather “weird” workaround involving placing tape on specific PINs on the PCI-e card to prevent the “RAM identify” issue noted by the Minisforum employee.

Is this a deal breaker?

I don’t think the bifurcation issue is necessary when you are thinking about it. Does the Minisforum MS-01 support bifurcation? The MS-01 has a healthy array of storage options for use in the unit anyway. Most will want to use bifurcation when adding multiple M.2 drives, I would think, but there are probably other use cases out there. Storage is just one I have dealt with personally in the home lab.

Let me know in the comments whether this is a deal breaker for you when considering the MS-01 in the home lab. How are you using bifurcation currently?

Review of the Minisforum MS-01

Check out my review of the Minisforum MS-01 in blog form here: Minisforum MS-01 Review: Best Home Server Mini PC Early 2024.

Also, check out the video review here:

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Brandon Lee

Brandon Lee is the Senior Writer, Engineer and owner at Virtualizationhowto.com and has over two decades of experience in Information Technology. Having worked for numerous Fortune 500 companies as well as in various industries, He has extensive experience in various IT segments and is a strong advocate for open source technologies. Brandon holds many industry certifications, loves the outdoors and spending time with family. Also, he goes through the effort of testing and troubleshooting issues, so you don't have to.

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