GPU_Switcher

A simple Powershell script that enables or disables my Laptop GPU depending on whether or not AC Power is connected to a laptop in Windows 11.

The problem

So, my Dell Precision 5470 was giving poor battery life (1 - 2 hours). After hours of investigating using HWiNFO, I found that it was the Nvidia A1000 Laptop GPU momentarily switching on and of for a few seconds at random. This is a known and unresolved problem discussed here. It was not only the GPU that had these spikes in power consumption, but it would also 'Wake-up' my CPU cores from their C-states, consuming even more power.

I did find that if I disabled the GPU in Device Manager, that:

1. The GPU did not register in HWiNFO and more importantly,
2. The power consumption of my laptop dropped way down to ~7 Watts at idle and ~10 Watts in general browsing - very acceptable in my opinion

However, it was tendious having to constantly check that the GPU was disabled when I unplugged my laptop from AC Power and then to have to do the reverse when I plugged it back in.

The solution

The solution was quite obviously to automate the task of enabling and disabling the GPU based on the state of AC Power.

Part 1 - Plug or Unplug while in use

I found this excellent article over on DEV.to that walked you through the enable/disable on the plug in/plug out event.

However, I found that on my laptop, the Event ID would trigger both the enable and disable scripts. This meant that, depending on which script was triggered first, the GPU enable/disable would either work as expected, or fail.

I modified the script to be an 'if' statement checker that checks the battery charging status as follows:

if ((Get-WmiObject -Class BatteryStatus -Namespace root\wmi -ComputerName "localhost").PowerOnLine -ne $true)
{
pnputil /disable-device "PCI\VEN_10DE&DEV_25B9&SUBSYS_0B291028&REV_A1\4&103D730F&0&0008"
}

if ((Get-WmiObject -Class BatteryStatus -Namespace root\wmi -ComputerName "localhost").PowerOnLine)
{
pnputil /enable-device "PCI\VEN_10DE&DEV_25B9&SUBSYS_0B291028&REV_A1\4&103D730F&0&0008"
}

This 'checker' was run in Powershell when triggered by the arguments:

-ExecutionPolicy Bypass -FILE "C:\GPU_EnableDisable\gpu_check.ps1"

The script works really well for me and is pretty much 'debugged'.

Part 2 - Check status at logon

To further extend this little script, I wanted the charging status of my laptop to be checked every time I restart, hibernate or sleep my laptop. This is because often I will close the laptop lid (put it to hibernate or sleep) and then unplug it. This 'unplug' would not be registered by the Part 1 event tracker. When I opened up the laptop again (with the power unplugged), the GPU would be enabled - which I didn't want.

This was a fairly simple task, using similar logic to the event tracker. Following the guide from Doctor Scripto, I created a task in Scheduler that would run every time I logged into my laptop. This 'on logon' approach was better than 'on startup' because it would cover all use cases from startup to waking the laptop up from sleep.

Conclusion

Now my laptop runs efficiently on battery and goes into power mode when I'm plugged into AC Power. A further tweak to the tasks was to run them with 'SYSTEM' priveldges. This prevented the Powershell window from opening, as disucssed here. I would suggest only changing this setting once you've tested the script and have your use cases running properly, otherwise you will not have a visual check on what happens when you plug/unplug AC Power