Predator PO3-640 after adding extra m.2 the speed is way low than expected

Marshall2000

Hi I'm after some help (first question of many)

I've just fitted an extra M.2 (1TB) to the empty slot on my pc (PO3-640) its a PCIE Gen 4 module so "should" be nice and quick. but i'm only getting the below speeds which are way lower than I had hoped for.

What speeds should i expect? or do i have a setting wrong?

Cheers

Tom

[Edited the thread to add issue detail]

Puraw

https://community.acer.com/en/discussion/728512/predator-po3-640-after-adding-extra-m-2-the-speed-is-way-low-than-expected

Hi Marshall2000,

Thanks for the CrystalDiskMark screenshot—those speeds (~800 MB/s) confirm the SSD is operating in SATA mode, not PCIe Gen4 x4. The M2_3 slot on the Predator PO3-640 is officially listed as PCIe Gen4 x4 capable, so you should be seeing speeds in the 3500–5000 MB/s range depending on the SSD model.

Let’s troubleshoot:

1. BIOS Detection

• Enter BIOS and check if the SSD is listed under NVMe devices.
• If it shows as SATA, update to the latest BIOS:🔗 https://www.acer.com/ph-en/support/product-support/predator-po3-640

2. SSD Firmware & Compatibility

• Use the SSD vendor’s tool (e.g., WD Dashboard, Samsung Magician) to update firmware.
• Confirm the SSD model supports Gen4 x4 and isn’t defaulting to SATA fallback.

3. Slot Wiring Confirmation

• Acer’s layout shows M2_3 as Gen4 x4, but if your SSD is still negotiating SATA, it may be a board-level wiring issue.
• Reference slot layout and user confirmations:

https://community.acer.com/en/discussion/701658/upgrading-m-2-ssd-on-predator-po3-640-is-there-a-list-of-compatible-m-2-ssds

4. Alternate Slot Test

• Try the SSD in M2_2 (boot slot) to confirm it negotiates PCIe x4 properly.

Let us know the exact SSD model and firmware version—this helps confirm whether it’s a drive-side fallback or a board-side limitation.