FAQ
TL;DR: Enabling Intel USB 3.0 mode can make USB 3.0 fall back to 2.0 speeds; fix it by updating BIOS and enabling xHCI. “Update the BIOS to the latest version.” [Elektroda, mieszaczwcz, post #16926755]
Why it matters: This FAQ helps ASRock H81M HDS and similar Intel-chipset users restore working USB 2.0/3.0 on Windows after BIOS or driver changes.
- ASRock H81M HDS board reported with USB issues after toggling Intel USB 3.0 Mode. [Elektroda, KeoPL, post #16926690]
- OS involved: Windows 7 Professional; USB stopped at desktop after reboot. [Elektroda, KeoPL, post #16926759]
- Key BIOS setting: set xHCI Mode to Enable to route ports to the USB 3.0 controller. [Elektroda, mieszaczwcz, post #16926755]
- Safe recovery: boot Safe Mode via F8 to handle driver crashes. [Elektroda, Pedros050, post #16926881]
- Use latest BIOS and drivers from the motherboard manufacturer site. [Elektroda, Pedros050, post #16926807]
Quick Facts
- ASRock H81M HDS with Intel USB 3.0 Mode toggled led to loss of USB 2.0 and non-working 3.0. [Elektroda, KeoPL, post #16926690]
- Windows 7 Professional environment; input devices died at desktop after restart. [Elektroda, KeoPL, post #16926759]
- Expert advice: “Update the BIOS to the latest version” and enable xHCI in BIOS. [Elektroda, mieszaczwcz, post #16926755]
- Boot Safe Mode with F8 to remove or roll back bad USB drivers. [Elektroda, Pedros050, post #16926881]
- Install only the motherboard vendor’s BIOS and USB drivers for stability. [Elektroda, Pedros050, post #16926807]
How do I fix USB not working after enabling Intel USB 3.0 Mode on ASRock H81M HDS?
Update the BIOS, then in BIOS set xHCI Mode to Enable. This routes ports to the USB 3.0 controller and stops USB 2.0 fallback. In Windows, confirm under Device Manager that devices attach to the xHCI controller. As one expert put it: “Update the BIOS to the latest version.” This sequence restored functionality for the case discussed. [Elektroda, mieszaczwcz, post #16926755]
Why do USB 3.0 devices run at USB 2.0 speed on Intel chipsets?
Ports can be redirected to the EHCI (USB 2.0) controller instead of the xHCI (USB 3.0) controller. Enabling xHCI Mode in BIOS and updating BIOS firmware resolves this routing and restores SuperSpeed operation. The guidance specifically warns that some USB 3.0 devices may only run at 2.0 speed until you correct the controller mapping. [Elektroda, mieszaczwcz, post #16926755]
What is xHCI vs. EHCI in simple terms?
xHCI is the USB 3.x host controller that enables SuperSpeed. EHCI is the older USB 2.0 controller. If BIOS routes ports to EHCI, devices cap at USB 2.0 speed. Set BIOS to xHCI Enable to hand ports to the USB 3.x controller. The original advice highlights checking which controller Windows uses in Device Manager. [Elektroda, mieszaczwcz, post #16926755]
How can I check which controller my USB ports use in Windows?
Open Device Manager and expand Universal Serial Bus controllers. Look for entries indicating xHCI or EHCI. Devices showing under xHCI use the USB 3.x path; under EHCI they use USB 2.0. If you see EHCI, enable xHCI Mode in BIOS and reboot, then recheck. The thread’s guidance explicitly recommends this verification step. [Elektroda, mieszaczwcz, post #16926755]
My mouse and keyboard stop working at the Windows 7 desktop—what now?
This symptom appeared after enabling Intel USB 3.0 Mode. Confirm Windows 7 loads, then USB input dies at the desktop. Use PS/2 input if available, or boot to Safe Mode to adjust drivers. After fixes, normal USB input returned for the reporter. They noted the failure within four minutes of their initial fix update. [Elektroda, KeoPL, post #16926759]
I get a blue screen after USB starts working—how do I recover?
Boot with F8 and choose Safe Mode. In Safe Mode, roll back or reinstall the USB drivers you changed before the crash. This lets you stabilize the system without loading the problematic driver set. The helper explicitly advised using F8 Safe Mode for driver issues. [Elektroda, Pedros050, post #16926881]
Where should I download USB and chipset drivers for ASRock H81M HDS?
Download only from the motherboard manufacturer’s website. Avoid mixed or generic packages. Install the latest BIOS and the vendor’s USB/chipset drivers, then reboot and test ports. The guidance in the thread stresses using the manufacturer site as the driver source. [Elektroda, Pedros050, post #16926807]
Do I need to update the BIOS before changing USB settings?
Yes. Update the BIOS first, then enable xHCI Mode. Firmware fixes controller routing and compatibility. Quoting the advice: “Update the BIOS to the latest version.” After that, set xHCI to Enable and verify in Device Manager. This sequence minimized USB 2.0 fallback behavior. [Elektroda, mieszaczwcz, post #16926755]
Is there a tool to map all USB controllers and devices?
Yes. Use USB Device Tree Viewer to inspect which devices sit on which controllers and hubs. It helps confirm if ports attach to xHCI or EHCI and reveals missing drivers. The helper shared this utility specifically to diagnose multi-controller setups. [Elektroda, Joker., post #16926796]
What does the BIOS “Intel USB 3.0 Mode” actually change?
It toggles how the firmware exposes USB 3.x capability to the OS. In the reported case, enabling it without proper drivers caused USB 2.0 to stop and 3.0 to remain inactive until fixes were applied. Correct setup later restored both generations. [Elektroda, KeoPL, post #16926690]
Three-step how-to: restore USB 3.0 speed on Intel chipsets
- Update motherboard BIOS to the latest release.
- In BIOS, set xHCI Mode to Enable.
- In Windows, confirm devices enumerate under the xHCI controller in Device Manager.
“Enable xHCI mode setting.” [Elektroda, mieszaczwcz, post #16926755]
Edge case: can some USB 3.0 devices be incompatible with Windows drivers?
Yes. The guidance notes some USB 3.0 devices are not compatible with the Windows 8 USB 3.0 driver stack. Check with your device vendor for firmware updates if issues persist after BIOS and xHCI changes. This is a known failure scenario addressed in the advice. [Elektroda, mieszaczwcz, post #16926755]
Should I reset BIOS to defaults if USB goes dark after changes?
Loading BIOS defaults is a safe first step if ports stop working after a setting change. Then reapply only essential changes, like enabling xHCI, and test again. This was suggested as an immediate recovery option in the thread. [Elektroda, mieszaczwcz, post #16926730]
Did the original poster ultimately resolve the USB issue?
Yes. After following the troubleshooting—BIOS, xHCI, drivers, and Safe Mode recovery—the poster confirmed, “everything works fine.” This indicates the approach restored stable USB operation on the ASRock H81M HDS. [Elektroda, KeoPL, post #16926896]
Was Windows 7 a factor in these USB problems?
Windows 7 Professional was the active OS when input stopped at the desktop. Driver handling and controller routing were central to the symptoms and the fix path described by helpers and the poster. Adjusting BIOS and driver sources resolved it. [Elektroda, KeoPL, post #16926759]
