Question PCIe Nvme SSD not using maximum lanes

[waseem749]

My Nvme using PCIe 3.0 x2 , when it has maximum capacity to run at PCIe 3.0 x4. how to enable it to use all four lanes available.

Hwinfo Screenshot https://ibb.co/kVWjxzMS
diskinfo screenshot https://ibb.co/jvCGzL9q

 

[kanewolf]

My Nvme using PCIe 3.0 x2 , when it has maximum capacity to run at PCIe 3.0 x4. how to enable it to use all four lanes available.

Hwinfo Screenshot https://ibb.co/kVWjxzMS
diskinfo screenshot https://ibb.co/jvCGzL9q

What CPU and motherboard? Which slot on the motherboard if there are multiple?

 

[waseem749]

there are three Pcie Slots , with configuration as follows and more info in Screenshot attached in thread of Hwinfo.

Computer
Computer Brand Name: HP HP Laptop 15-da1xxx

Motherboard
Motherboard Model: HP 8532
Motherboard Chipset: Intel Cannon Lake-U PCH-LP Premium
Motherboard Slots: 2xPCI Express x1, 1xPCI Express x4
PCI Express Version Supported: v3.0
USB Version Supported: v3.1

BIOS
BIOS Manufacturer: Insyde
BIOS Date: 04/26/2024
BIOS Version: F.48
UEFI BIOS: Capable

Super-IO/LPC Chip: Unknown
Trusted Platform Module (TPM) Chip: Hardware TPM, version 2.0

Processor Name: Intel Core i3-8145U
Original Processor Frequency: 2300.0 MHz

CPU ID: 000806EB
CPU Brand Name: Intel(R) Core(TM) i3-8145U CPU @ 2.10GHz
CPU Vendor: GenuineIntel

 

[JeffreyP55]

My Nvme using PCIe 3.0 x2 , when it has maximum capacity to run at PCIe 3.0 x4. how to enable it to use all four lanes available.

Hwinfo Screenshot https://ibb.co/kVWjxzMS
diskinfo screenshot https://ibb.co/jvCGzL9q

Refer to your user manual. You
may have selected a slot that runs @ x2 for a reason. Some slots share robbing lanes. How old is your MB? Will it run at 3x?
Without any PC details will not work. Full details please.

 

[waseem749]

Refer to your user manual. You
may have selected a slot that runs @ x2 for a reason. Some slots share robbing lanes. How old is your MB? Will it run at 3x?
Without any PC details will not work. Full details please.

Motherboard Slots: 2xPCI Express x1, 1xPCI Express x4

ssd installed on 1xPCI Express x4 and ethernet and Wifi cards on 2xPCI Express x1.

 

[waseem749]

User manual http://h10032.www1.hp.com/ctg/Manual/c06691790.pdf

 

[evermorex76]

there are three Pcie Slots , with configuration as follows and more info in Screenshot attached in thread of Hwinfo.

Where are you getting this information? Laptops don't have standard PCIe slots. What is the EXACT model of your laptop, not "xxx"? The i3 CPU doesn't have any PCIe lanes for an M.2 slot, so it has to be running off the PCH, which only has 4 additional lanes. If there is any PCIe device connected, like your Ethernet and Wi-Fi adapters, the M.2 slot would only have 2 available. The manual for the HP 15 laptop says the top read speed is 2150MBps, which is about right for PCIe3 x2 (they seem to be exaggerating a bit, or rounding up, or using decimal instead of binary). Other references to the 15-da1xxx models confirm it is only x2. This is common in lower-end laptops and those with the lower-end chipsets/CPUs.

 

[SkyNetRising]

Computer Brand Name: HP HP Laptop 15-da1xxx

It seems to be limitation imposed by laptop manufacturer.
M.2 slot can run in x1 , x2 and x4 modes.

In this document M.2 drive speed limit is mentioned - page 89 ( 2150 MB/s for sequential reads/writes).
PCIE 3.0 x4 is ~ 3500MB/s. So you get ~ half of that.

https://h10032.www1.hp.com/ctg/Manual/c06691790.pdf

There may be options in BIOS to change M.2 slot operation mode.
Check it.

 

[JayGau]

evermorex76 might be right. If the CPU doesn't have any PCIe lanes, then all the lanes have to go to the chipset. So the three m.2 slots might share the four chipset lanes. Since two are used by the network adapters, there are only two left for the drive. So in theory, the slot for the drive "can" run at x4 but in reality it doesn't because of the other devices using half the lanes.

It's like manufacturers saying in their ads that their motherboards have x NVMe slots but avoid mentioning that one of them shares the lanes with the x16 PCIe slot so if you use it your GPU will run at x8.

 

[waseem749]

It seems to be limitation imposed by laptop manufacturer.
M.2 slot can run in x1 , x2 and x4 modes.

In this document M.2 drive speed limit is mentioned - page 89 ( 2150 MB/s for sequential reads/writes).
PCIE 3.0 x4 is ~ 3500MB/s. So you get ~ half of that.

https://h10032.www1.hp.com/ctg/Manual/c06691790.pdf

There may be options in BIOS to change M.2 slot operation mode.
Check i

Where are you getting this information? Laptops don't have standard PCIe slots. What is the EXACT model of your laptop, not "xxx"? The i3 CPU doesn't have any PCIe lanes for an M.2 slot, so it has to be running off the PCH, which only has 4 additional lanes. If there is any PCIe device connected, like your Ethernet and Wi-Fi adapters, the M.2 slot would only have 2 available. The manual for the HP 15 laptop says the top read speed is 2150MBps, which is about right for PCIe3 x2 (they seem to be exaggerating a bit, or rounding up, or using decimal instead of binary). Other references to the 15-da1xxx models confirm it is only x2. This is common in lower-end laptops and those with the lower-end chipsets/CPUs.

laptop model Hp 15 Da1013ny has Intel I3 8145U Cpu which i guess has 16 lanes, in the following configuration 1x4, 2x2, 1x2+2x1 and 4x1. the one slot with 4 lanes is where my Nvme Located,

 

[evermorex76]

laptop model Hp 15 Da1013ny has Intel I3 8145U Cpu which i guess has 16 lanes, in the following configuration 1x4, 2x2, 1x2+2x1 and 4x1. the one slot with 4 lanes is where my Nvme Located,

I had to look further because I was unclear on the way the lanes are laid out on this processor, because the CPU and PCH are integrated on the same package and treated as one, even though they're physically different chips. I simply can't find a good diagram that confirms how the lanes are laid out, because "Cannon Lake-U" is randomly used to refer to just the PCH or both the PCH and CPU (since they're in a single package) with Whiskey Lake being the CPU itself. Even Intel doesn't refer to Cannon Lake-U as anything, except in diagrams where they show it paired with Whiskey Lake but don't show which parts drive what lanes.

The HP 15 model does have discrete graphics as an option according to the manual (unfortunately HP is absolutely terrible about listing their models and options, and won't even show base specs without providing a serial number for your specific machine), so it's almost certain that the x4 slot would be routed to the location where such a GPU would be mounted. Those likely connect directly to the CPU, as well as the 2x2 and 1x2+2x1, and the 4x1 are driven by the chipset portion. That would match the usual layout of mobile chipsets. So the M.2 slot would only be able to use one of the x2 pairs. The chipset's lanes almost certainly drive the Wi-Fi slot and the network controller/PHY.

Crucial does claim that the laptop has an x4 slot, however that's the ONLY place that attempts to make that claim with any confidence, and they're not always right. The fact that HP's manual doesn't specify it, and that it's a low-end mobile CPU and laptop, and the simple fact that your drive is only running at x2 (standard laptops don't have BIOS options that can change that) make me very sure that your system only supports 2 lanes for the NVMe SSD. My sister even has an HP desktop system that only supports 2 lanes.

 

[waseem749]

I had to look further because I was unclear on the way the lanes are laid out on this processor, because the CPU and PCH are integrated on the same package and treated as one, even though they're physically different chips. I simply can't find a good diagram that confirms how the lanes are laid out, because "Cannon Lake-U" is randomly used to refer to just the PCH or both the PCH and CPU (since they're in a single package) with Whiskey Lake being the CPU itself. Even Intel doesn't refer to Cannon Lake-U as anything, except in diagrams where they show it paired with Whiskey Lake but don't show which parts drive what lanes.

The HP 15 model does have discrete graphics as an option according to the manual (unfortunately HP is absolutely terrible about listing their models and options, and won't even show base specs without providing a serial number for your specific machine), so it's almost certain that the x4 slot would be routed to the location where such a GPU would be mounted. Those likely connect directly to the CPU, as well as the 2x2 and 1x2+2x1, and the 4x1 are driven by the chipset portion. That would match the usual layout of mobile chipsets. So the M.2 slot would only be able to use one of the x2 pairs. The chipset's lanes almost certainly drive the Wi-Fi slot and the network controller/PHY.

Crucial does claim that the laptop has an x4 slot, however that's the ONLY place that attempts to make that claim with any confidence, and they're not always right. The fact that HP's manual doesn't specify it, and that it's a low-end mobile CPU and laptop, and the simple fact that your drive is only running at x2 (standard laptops don't have BIOS options that can change that) make me very sure that your system only supports 2 lanes for the NVMe SSD. My sister even has an HP desktop system that only supports 2 lanes.

if you see into Hwinfo screenshot https://ibb.co/kVWjxzMS , it states that My Nvme is installed on Intel Cannon Lake-LP - PCI Express Root Port #13 , which has Maximum Lanes Alloted x4 but currently x2 are being used.

 

[rgd1101]

probably mean the controller can do x4 but your laptop can only do x2.

 

[evermorex76]

probably mean the controller can do x4 but your laptop can only do x2.

Exactly. The controller CAN do 4 lanes, but HP likely only wired it for 4. Makes it very very very slightly cheaper for them and easier to design the motherboard with fewer electrical traces required.

The sole other possibility is damage to the drive or the slot resulting in some of the pins not connecting. Try that drive in another machine that is known to be working properly, and try another drive in your laptop.

Short of contacting HP to ask or opening the machine to try to examine the slot contacts where they meet the board (which you probably can't see), I don't think you're going to find any solid confirmation and just have to accept that this is the way the system is designed. There simply isn't any way to change the number of lanes outside of a BIOS setting or physically not connecting them.

Interesting that they would choose to use the sole x4 root port and only wire it for x2. How could the possibly offer the same model of laptop with a discrete graphics option using the same system? Maybe on those machines they actually move the M.2 slot to use an x2 root, but that would mean designing different motherboards instead of simply using the same board and leaving out the GPU. It would however ensure that getting a GPU didn't result in losing performance on the M.2 port compared to the non-GPU models.