PCIE Lane Count for NVMe slot on 14-dk1031dx

[Drewcifer1]

I recently got a WD Black 770 SSD.  I plugged it into the NVME storage expansion slot.  All is going well except the drive is running at Gen3x2 speeds instead of what I expected, Gen3x4.  As confirmed by WD Dashboard, HWinfo, and a winsat test.  In the laptop there is an AMD Ryzen 3 3250U cpu, the motherboard model is HP 879E, and chipset is AMD Promontory/Bixby FCH.  Is this an issue with the UEFI not allowing 4 lanes or is it a hardware issue? Can I get this fixed by an IT professional?

I tried reinstalling the ssd a few times, didn't work. Secure boot on/off didn't change anything. The UEFI has a locked Advanced tab, I cannot access it.

It also is switching back to Gen2x2 speeds when I unplug the laptop from AC power. Can I change this? 

[Irfan_06 · Accepted solution]

Hi @Drewcifer1,

Welcome to the HP Support Community.

Thank you for posting your query, I will be glad to assist you.

The behavior you're describing, where your NVMe SSD is running at Gen3x2 speeds instead of Gen3x4, may stem from several potential factors related to your laptop's hardware, BIOS/UEFI settings, and power management configurations.

Here’s a breakdown of what could be happening:

1. PCIe Lane Limitation

• The AMD Ryzen 3 3250U is a dual-core processor that generally supports PCIe 3.0 with limited lane availability. It may be that the laptop's motherboard (HP 879E) allocates only two PCIe lanes to the NVMe slot, limiting your drive to Gen3x2 speeds. This is common in budget and mid-range laptops where the NVMe slot may be wired for only two lanes instead of four.
• The chipset (AMD Promontory/Bixby) typically supports PCIe 3.0 x4 for the primary NVMe slot, but it might be limited by the motherboard design or how the laptop manufacturer has implemented it.

2. UEFI/BIOS Configuration

• If the Advanced tab in the UEFI is locked and you cannot access the settings, it's likely that HP has restricted user access to certain configurations (such as PCIe lane allocation). The UEFI/BIOS could be limiting the NVMe slot to x2 lanes instead of x4.
• Some laptops also restrict NVMe performance depending on power settings or power-saving modes. The fact that the SSD switches to Gen2x2 speeds when unplugged from AC power suggests that this might be a power management feature to save energy, possibly limiting the number of active lanes when running on battery.

3. Power Management Impact

• When the laptop is unplugged from AC power, the power-saving modes could be automatically throttling the PCIe lanes to save battery. This is why your SSD reverts to Gen2x2 speeds on battery power. It is also possible that the laptop's power management system reduces PCIe performance to optimize for energy efficiency, limiting it to Gen2x2 or even Gen1 on battery.

4. Firmware/Driver Update

• Ensure that your UEFI/BIOS is up to date. Sometimes, an update can resolve compatibility issues or unlock additional performance features for NVMe SSDs.
• Also, make sure that the NVMe drivers and any chipset drivers are up to date. Sometimes these can affect the speed and number of lanes used by an NVMe drive.

Possible Solutions:

• Check for BIOS/UEFI Updates: Update the BIOS for your PC by clicking on the link.

Make sure you keep only the charger plugged in while updating the BIOS for your PC.

Click on the + sign next to BIOS and then download the file.

Open the file and follow the on-screen instructions to complete the update.

• Adjust Power Settings: Go into your power settings and set the laptop to high-performance mode to prevent the power-saving throttling from reducing the PCIe lane count. Additionally, make sure that any power-saving features in the UEFI are set to maximum performance.

In conclusion, the limited lane count is most likely a hardware limitation in your laptop's motherboard or processor design. While it's not an "issue" that can be easily fixed by an IT professional without altering the hardware, an update to your BIOS/UEFI or optimizing power settings could help improve performance where possible. However, if the laptop is physically wired for only x2 lanes, then Gen3x2 will be the maximum achievable speed.

Please mark this post as “Accepted Solution” if the issue is resolved and if you feel this reply was helpful click “Yes”.

I hope this helps.

Take care and have a great day ahead!

Irwin6

HP Support