Thanks — that’s very useful. Given the onboard Realtek works reliably on cold boot and the PCIe Realtek 2.5Gb card only works after a reboot, this is almost certainly a hardware/initialisation issue specific to that PCIe card or the combination of card + slot/firmware. Because you don’t have a spare machine/slot for long‑term testing, we have three practical paths (least work → most reliable):
Summary of options
- A — Try a clean driver reinstall (software-first, low effort). Sometimes driver packaging leaves fragments that cause cold‑boot failures.
- B — Tweak BIOS power/PCIe settings and adapter power features (firmware / power sequencing). This can fix slot initialisation timing without replacing hardware.
- C — Replace the PCIe card (hardware). If A+B fail, card is likely faulty or incompatible and replacement is the long‑term fix. Meanwhile use onboard NIC.
Which do I recommend you try first?
Do A (clean driver uninstall + reinstall vendor installer) and B (disable energy features / BIOS tweaks) if you want to try to fix it. If you prefer to avoid more troubleshooting, stick with the onboard NIC and replace the PCIe 2.5Gb card later.
If you want to try A and B now, here are the exact, safe steps and the single commands to run. I’ll wait while you do each one and you can report the results.
A — Clean driver uninstall and reinstall vendor installer (safe)
1) List Realtek driver packages in the driver store (just to see them):
pnputil /enum-drivers | findstr /i Realtek
2) Export current Realtek drivers for backup (optional, safe):
Create a folder first, then export:
md C:\DriverBackup
pnputil /export-driver oem* C:\DriverBackup
(If that exports many drivers it’s OK — you’ll have a backup.)
3) Remove Realtek driver packages (use the oem name(s) you saw with step 1)
Example (replace oemN.inf with the exact name found):
pnputil /delete-driver oem9.inf /uninstall /force
pnputil /delete-driver oem7.inf /uninstall /force
(You can repeat for each Realtek oem driver listed.)
4) Reboot (clean state):
shutdown /r /t 5
5) Install the Realtek vendor installer you downloaded (run as Admin):
Start-Process -FilePath "C:\Path\Install_Win11_Win10_10077_20_08282025.exe" -Verb RunAs -Wait
(Replace the path with the actual file path.)
6) Reboot again and test cold boot. If it still fails, go to B.
B — Disable adapter energy features and check BIOS power settings (safe & reversible)
1) Show exact advanced property names (copy/paste the output):
Get-NetAdapterAdvancedProperty -Name "Ethernet" | Where-Object DisplayName -match 'Green|Gigabit|EEE|Energy' | Format-Table DisplayName,DisplayValue -AutoSize
2) Disable the relevant features (example commands). Run only after you confirm property names in step 1:
Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Green Ethernet" -DisplayValue "Disabled"
Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Gigabit Lite" -DisplayValue "Disabled"
Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Advanced EEE" -DisplayValue "Disabled"
Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "EEE Max Support Speed" -DisplayValue "Disabled"
3) In BIOS/UEFI (reboot to firmware)
- Disable PCIe ASPM / Link State Power Management (if present).
- Disable ErP / deep sleep / Sx power settings.
- Set PCIe slot power/performance to maximum (if option exists).
Save & reboot and do cold‑boot tests.
C — Replace the card (if A+B fail)
- If both A and B fail, the card is likely defective or incompatible with that motherboard slot/timing. Replace with another PCIe 2.5Gb or use a USB 2.5G adapter. Recommended chipsets: Intel I225 (Intel-based) or known-good Realtek/Marvell cards from a reputable vendor. Keep the onboard NIC enabled as a fallback.
If you want to proceed now, tell me:
- “Do A” to run the clean uninstall (I’ll give the one‑line to list drivers now and the exact pnputil deletes after you paste the pnputil list), or
- “Do B” to disable energy features (I’ll give the Get‑NetAdapterAdvancedProperty command so you can confirm exact DisplayName values, then the disable commands), or
- “Replace” and I’ll recommend replacement cards and exact steps to prepare an RMA/replacement.
Which do you want to try first?