HP Z620 - Question on PCIe slot split to 4x4 to support add-on SSD cards

[aliz00]

Hi,

I have a desktop HP Z620 running with Window 10 Enterprise.

I would like to add some M.2 SSD drives to it using a PCIe to M.2 card adapter such as this one:

https://www.scan.co.uk/products/asus-hyper-m2-x16-card-v2-pcie-30-x16-4x-m2-pcie-2242-60-80-110-slot... (ASUS 90MC06P0-M0EAY0).

Looking on the internet, it looks like I need to verify two things to make it work:

  - that the motherboard supports PCIe splitting (ideally from the existing PCIe 3 x16 slot to 4x4 slots)

  - that the BIOS will allow me to access all 4 drives at the same time

How can I find out whether this is the case on my Z620? I am new to this technology so I am not even sure of how to phrase my question on the support pages!

Thank you in advance for your help,

Aliz00

[Brian1965 · Accepted solution]

Hi Aliz00,

Unfortunately, the HP Z620 does not support bifurcation, (splitting of the PCIe lanes), this feature only appeared on the next generation of of HP workstations, e.g. HP Zx40 series. There is an additional slot setting in the HP Zx40 BIOS to select this feature. (Please read this post).

Looks like you are limited to a standard PCIe x4 M.2 card and just adding a larger M.2 SSD card.

[aliz00]

Hi Brian1965,

Thank you for your answer, this is what I feared. For my future understanding, is there a way for me to find out whether bifurcation is supported by a mother board for any given computer? I have a few other desktops including a few HP ones in the lab that I could swap with but that info doesn't seem to be on any tech spec. Unless perhaps it is specified under  different name?

Second idea, although my Z620 doesn't support bifurcation,  it does have a lot of PCIe slots including 4 Gen 3 ones:

• Slot 1 (top): PCI Express Gen2 x4(1), full-height, half-length
• Slot 2: PCI Express Gen3 x16, full-height, full-length (with extender)
• Slot 3: PCI Express Gen2 x8(4) with open-ended connector, full-height, full-length (with extender)
• Slot 4: PCI Express Gen3 x8 with open-ended connector, full-height, full-length (with extender)
• Slot 5: PCI Express Gen3 x16, full-height, full-length (with extender)
• Slot 6: PCI 32-bit/33 MHz, full-height, full-length (with extender)

What if instead of my original bifurcation idea, I were to purchase  three PCIe to M.2 adapter  and plug one SSD drive into each of them? Would the bios still be a limitation to writing to all three drives in parallel?

What I am really after is true disk writing speed using Windows 10: I need  >1500 MB/s sustained for over an hour and  working reliably. My current SSD is an old 2.5" which really isn't up to the task.  Looking at different options, and comparing "real life" writing speeds (from https://ssd.userbenchmark.com and taking into account software and windows limitations) it seems to me that the M.2 SSD drives are the most economical options but that I would still need two or three in parallel to achieve the rate required by the time I take into consideration all the losses from my software and interfaces.

Please let me know what you think of my second option. Any other idea or advice would be great too!

Aliz00

[Brian1965]

Hi Aliz00,

With regards to your questions;

"is there a way for me to find out whether bifurcation is supported by a mother board for any given computer?" - If you have access to these machines you could easily check if bifurcation is supported by checking the BIOS options for each system. As I mentioned, the HP Zx40 series of computers do support bifurcation. Bifurcation appears to be only available on newer, fully compliant UEFI BIOS systems. (You could also check if the CPU supports bifurcation at the Ark Intel site).

"What if instead of my original bifurcation idea, I were to purchase three PCIe to M.2 adapter and plug one SSD drive into each of them? Would the bios still be a limitation to writing to all three drives in parallel?" - Adding multiple M.2. PCIe cards and drives is a possible option and will be displayed as seperate physical drives in Windows. I'm not sure if you would be able to RAID multiple M.2. drives on the Z620 platform since this system doesn't have a fully compliant UEFI BIOS or support VROC.

I would be tempted to start by adding a single fast M.2. card, (e.g. 1TB 970 EVO Plus is known to work as a data drive in the Z620), then add additional M.2. drives later if required.

If you do source a VROC compliant system and want to set up an M.2. RAID, then I would suggest you read this. It lists all VROC compatible M.2. drives.

[DGroves]

ssd raid on a z620 is rather pointless, unless you can actually use the increased sequential transfer speed

also keep in mind that the z620 does not support Booting from NVME devices unless you use a preboot loader such as GUET+REFIND which loads the missing nvme code into ram before the system boots into the windows OS

for most users, the ssd'd RANDOM ACCESS speeds are the most important metric and this is not really improved when using Raid modes

if your needs do favor sequential access then look at several ssd carriers that hold 2/4 ssd's and do not require bifurcation keep in mind that these professional products have price tags to match!! here's a few links (there are others)

https://www.amfeltec.com/pci-express-carrier-boards-for-m-2-ssd-modules/

https://www.sonnettech.com/product/m2-4x4-pcie-card.html

https://www.amazon.com/CREST-SI-PEX40129-Ports-Bifurcation-Controller/dp/B07HYZY7P2

[aliz00]

Hi Brian1965 and DGroves,

Thank you both for your inputs on my problem, I understand what I need to look for now. I will continue my investigation and trials and I will post the final solution and the speed achieved in this thread.

Thank you!