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Nick94733
1 Copper

Motherboard voltage throttling?

When I play a game, if my Alienware (late 2014) model with Nvidia 860M GPU

is not plugged in, the monitor goes dim and the USB ports stop providing voltage to external devices, the system then recognizes this as an unplugged device... This is *NOT* a system issue, as I have thoroughly checked the system settings and ensured that the system is not set to dim screen in the event it is unplugged from the AC Adapter, could this be the motherboard cutting back on the voltage being used to power the monitor and external devices? (in this case 1 mouse was connected via USB dongle)

Does anyone have any similar issues, or is this outside of the norm?

Thank You

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4 Replies
8 Krypton

RE: Motherboard voltage throttling?

The default power management setting will dim the display on battery -- did you check BOTH the Windows settings and the system setup (UEFI) settings?  The latter will over-ride the former.

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kirkd
4 Ruthenium

RE: Motherboard voltage throttling?

Have you monitored voltages, temperatures, etc. while this happens? Use Open Hardware Monitor, which shows everything, including power draws. BattStat also monitors power in/out and out as well as other battery parameters. 

It's possible the battery is not supplying as much power as needed during gaming. A new, higher wattage battery and power supply could help. If the battery is older, it may not be able to provide the power level needed.

I don't think any feature will shut off power to a USB port. 

XPS M1530, Win 10 CU Pro 32-bit
Inspiron E1705, Win 10 CU Pro 32-bit
Dimension 9100, Win 10 AU Pro 32 bit
Inspiron 660, Win 10 CU 64 bit
Inspiron 3668, Win 10 CU 64 bit
Asus T100 Tablet, Windows 10 CU 32 bit

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Nick94733
1 Copper

RE: Motherboard voltage throttling?

UEFI settings were just checked, everything is normal.

Voltage testing with performance monitor will begin tomorrow night, hopefully I can gather some useful data.

The alienware device I am using, is less than 2 months old, so hopefully it's not an issue with motherboard.

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Nick94733
1 Copper

RE: Motherboard voltage throttling?

Preliminary test results are in: It can be seen below, that the GPU usage drops significantly right about the time that the USB ports stop and the screen dims.

EDIT: this is inconclusive, as the GPU drop could be a result of exiting the game soon after screen goes dark. Further testing is needed, while staying in game for prolonged periods of time to give accurate time representation of issue.

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