[SOLVED] My U.2 NVME SSD is using only 1 PCIe lane ?

[laurezard]

Hello forum! It's been a long time since I've had to post to Tom's for help, but I'm at a loss as to what to do here.

I recently got a U.2 NVME SSD and installed it on my Biostar Z270GT6 mobo using a Mini SAS (SFF-8643) connector. I have 4 other drives connected via SATA, as well as an M.2 in the board's M.2 slot.

I did read the mobo manual before purchasing this U.2, and all it says is that if you connect a U.2, you can no longer use two of the SATA ports. This is no problem, and I shuffled my SATA drives around so that they are not occupying those ports. All of the SATA drives as well as the M.2 are working perfectly. The U.2 is functional, but crystaldiskinfo tells me that it is only using 1 PCIe lane, instead of the 4 lanes it is capable of. It's pretty fast, hitting over 800 MB/s read and write in crystaldiskmark. But I know it could be running much faster if only I could get it to use more PCIe lanes.

I looked around in my BIOS, and while there is an "NVME Configuration" section there, everything is grayed out and I can only read a few basic details about the installed M.2 and U.2 drives.

There shouldn't be any conflict between the U.2 and M.2, as the mobo manual doesn't mention that. Using the M.2 slot disables one of the PCIe x 16 slots, but it's not one I'm using anyway.

Please, if you have any idea what I can do to get my U.2 to use more than just 1 PCIe lane, I would be so grateful! Thanks for any input!


Less important question: When I installed this U.2 last night, one of my RAM slots stopped working. I tested the sticks and they are all functional. If I use a certain slot, my mobo throws code 55 (RAM not detected), so now I am just using 3 sticks instead of 4. I'll probably make another post for this, but if you know what could've caused this, please let me know.

 

[Lutfij]

Out of curiosity, what BIOS version are you working with for your motherboard at the time of writing? Make and model of your U.2 drive? Got a link from where you purchased the drive off of?

 

[Karadjgne]

Max PCI-E Storage (x4 M.2 or x2 SATA Express) = 3. You have 24 pcie chipset lanes but some of those are already spoken for, used for other stuff other than storage. What the manual doesn't tell you is that using the U.2, M.2 and full Sata complement is too much and expect the full x4/x2 from each. The Primary gpu slot uses cpu dedicated lanes, so is exempt, but all other slots, including the pcie x1 and x4 slots will use the chipset lanes, some slots sharing connectivity, so the x16 and x1 will share etc. If using the x16, you get x16, if also using the x1 then you get x8 instead.

Can only split it up so many ways.

 

[laurezard]

Out of curiosity, what BIOS version are you working with for your motherboard at the time of writing? Make and model of your U.2 drive? Got a link from where you purchased the drive off of?

Here's a link to the drive, a WD SN630. Pretty good deal imo. https://eshop.macsales.com/item/Western Digital/0TS1619/

As for the BIOS version, not sure and I'm not at home right now..

 

[laurezard]

Max PCI-E Storage (x4 M.2 or x2 SATA Express) = 3. You have 24 pcie chipset lanes but some of those are already spoken for, used for other stuff other than storage. What the manual doesn't tell you is that using the U.2, M.2 and full Sata complement is too much and expect the full x4/x2 from each. The Primary gpu slot uses cpu dedicated lanes, so is exempt, but all other slots, including the pcie x1 and x4 slots will use the chipset lanes, some slots sharing connectivity, so the x16 and x1 will share etc. If using the x16, you get x16, if also using the x1 then you get x8 instead.

Can only split it up so many ways.

Thank you so much for your response, it clears some things up for me. Sorry for the late reply. Yeah, before I bought it, I was wondering how many lanes the drive would be able to use since I have so many things hooked up in my system.
This leads me to a few more questions, if you could help...

Would removing some of the SATA drives from my system increase the amount of lanes usable by the new U.2? (I was planning to do this anyway, after I finish backing up the files from them.)

Is there any software solution similar to CrystalDiskInfo that is able to identify what lanes are used by what hardware in my system? Or perhaps, is that a feature that some mobos/BIOS have?

Finally, does the labelling on the board diagram in the mobo manual typically give hints as to what lanes each port uses? Eg: Can I assume that "PEX1_4," a PCIe slot on the mobo is sharing lanes with SATA3_4U and SATA3_4L just because they are both labelled "4?"

Thanks for your help.

 

[Karadjgne]

1. Yes. All drives that are present will soak up at least 1 lane minimum as windows will insist on keeping them active, even if not actively used. So removing drives logically would decrease the amount of lanes used.

2. Not that I've ever heard of, since it changes based on demand and chipset. My X570 is pcie4.0 capable everything, has 16x cpu lanes dedicated to pcie slot 1, and 4x cpu lanes dedicated to M.2 slot 1. All other lanes are from the X570 chipset and some ports share lanes, but even that's not an issue since pcie4.0 x4 is the same bandwidth as pcie3.0 x8.

11thgen Intel isn't so lucky, it's all pcie3.0 , nor is B550 which only has cpu lanes at pcie4.0.

That shows my board pcie split up. Yours will be somewhat similar, with how the lanes are split. Your issue right now (I believe) is your Flexible Pcie are stretched thin by too much dependency. To many little drives.

 

[Karadjgne]

1. Yes. All drives that are present will soak up at least 1 lane minimum as windows will insist on keeping them active, even if not actively used. So removing drives logically would decrease the amount of lanes used.

2. Not that I've ever heard of, since it changes based on demand and chipset. My X570 is pcie4.0 capable everything, has 16x cpu lanes dedicated to pcie slot 1, and 4x cpu lanes dedicated to M.2 slot 1. All other lanes are from the X570 chipset and some ports share lanes, but even that's not an issue since pcie4.0 x4 is the same bandwidth as pcie3.0 x8.

11thgen Intel and prior isn't so lucky, it's all pcie3.0/2.0, nor is B550 which only has cpu lanes at pcie4.0 and chipset at 3.0

That shows my board pcie split up. Yours will be somewhat similar, with how the lanes are split. Your issue right now (I believe) is your Flexible Pcie are stretched thin by too much dependency. To many little drives.

3. Not the way you'd like. You have Flexible lanes from the chipset. They can be used for anything. So the only thing that's visible by the labeling would be those have a 4 in the title. None are dedicated as such, they just have access. With your board, gotta read the specs, I believe that if using one of the M.2, it disables Sata 5/6 etc. That'll be in *notations at the bottom of the page.

 

[laurezard]

1. Yes. All drives that are present will soak up at least 1 lane minimum as windows will insist on keeping them active, even if not actively used. So removing drives logically would decrease the amount of lanes used.

2. Not that I've ever heard of, since it changes based on demand and chipset. My X570 is pcie4.0 capable everything, has 16x cpu lanes dedicated to pcie slot 1, and 4x cpu lanes dedicated to M.2 slot 1. All other lanes are from the X570 chipset and some ports share lanes, but even that's not an issue since pcie4.0 x4 is the same bandwidth as pcie3.0 x8.

11thgen Intel and prior isn't so lucky, it's all pcie3.0/2.0, nor is B550 which only has cpu lanes at pcie4.0 and chipset at 3.0

[helpful pic]

That shows my board pcie split up. Yours will be somewhat similar, with how the lanes are split. Your issue right now (I believe) is your Flexible Pcie are stretched thin by too much dependency. To many little drives.

3. Not the way you'd like. You have Flexible lanes from the chipset. They can be used for anything. So the only thing that's visible by the labeling would be those have a 4 in the title. None are dedicated as such, they just have access. With your board, gotta read the specs, I believe that if using one of the M.2, it disables Sata 5/6 etc. That'll be in *notations at the bottom of the page.

Thank you, I really appreciate you taking the time to answer! This gives me a lot to think about for my next build. On my board, the M.2 connection disables one of my PCIe x16 (x4) slots, and the U.2 disables two of the SATA slots (which I have empty right now). That's really all the manual says. But your answer has helped me understand how these lanes are used beyond just what is written in the mobo manual. So, I should be able to manage them now. Thanks again!!