Why do my NVMe disk work at PCI1 x2 mode?

[Stalkerr]

Hi!

My NVMe disk is support PCI3 x4 mode, but it work at PCI1 x2. How can I solve this issue?

Factory installed disk is support PCI3 x2 mode, but work at PCI2 X2.

In Windows and in Linux I see same NVMe port working mode.

[erico]

Hi @Stalkerr 

Unfortunately, you may be comparing apples to oranges.

SATA3 and NVMe SSD products work at  the bandwidth that their chipsets permit.

The only time that PCIe x4 and x2 come into playe is if compatible SSD products are installed in an desktop PC. 

The distinction between PCIex4 and PCIE x2 only exists in desktop PC motherboards. not laptop system boards.

If you want to see a useful  performance measure of an SSD, then use a benchmark utility.

https://www.gearprimer.com/technology/best-hdd-ssd-benchmarks-test-storage-speed. In the enthusiast worls, the top two in the article are what most people use.

[Stalkerr]

I don`t compare write or read speed of the disks. I whant to understand  why company in specification declares NVMe PCIe M.2 port as PCIe3 x4, and different disks whith specification PCIe3 x4 does`t work whith this port.

Factory disk, by disk specs have PCIe3 x2 mode. In realty work at PCIe2 x2. In HP specs it is declared as 256 GB PCIe Gen 3x4 NVMe SSD.

Kingston NVMe PCIe3 x4 work at PCIe1 x2.

Current Crucial PCIe3 x4 work at  PCIe1 x2 also.

I`m talk about the NVMe M.2 port that is soldered to the motherboard of my laptop. Not the L22542-001.

I`m talk about this, and this is not sata3.

M.2 PCIe solid-state drive specifications
Table 10-4 Solid-state drive specifications
256-GB*
Dimensions
Height 1 mm
Length 50.8 mm
Width 28.9 mm
Weight < 10 g
Interface type ATA-7
Transfer rate
Sequential Read Up to 2150 MB/s
Random Read Up to 300,000 IOPs
Sequential Write Up to 1260 MB/s
Random Write Up to 100,000 IOPs
Ready time, Maximum (to not busy) 1.0 s
Access times
Logical 0.1 ms
Total logical sectors 500,118,192
Operating temperature
Operating 0° to 70°C (32°F to 158°F)
Non-operating -40° to 80°C (-40°F to 176°F)

[erico]

I highly recommend that you consider using a benchmark instead of looking at a specification.

Companies program BIOS to do what they decide to do in consideration of the target market segment and the  tier that a notebook fits into.

That is something neither of us can influence.

[Stalkerr]

@Erico .

What do you want to tell me? That HP is lying about its stats. Well, if I knew that, I would not buy this laptop.

Yes, I have already done the tests, and I am clearly sure that the drive is connected to the motherboard with two PCIe lanes, the total read and write speed corresponds exactly to two lanes.

lspci -vv

03:00.0 Non-Volatile memory controller: Micron/Crucial Technology Device 5403 (rev 03) (prog-if 02 [NVM Express])

LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <8us
ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
LnkCtl: ASPM L1 Enabled; RCB 64 bytes Disabled- CommClk+
ExtSynch- ClockPM+ AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 8GT/s (ok), Width x2 (downgraded)
TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-

[erico]

I have asked HP internally about the discrepancy between the specifications and the Maintenance guide. 

I won't know more about this until I hear back from them.