Surface Book 3 15-inch experiences power drain when using 1798 power supply

Hi XMTX,

Thank you for reaching out to Microsoft Q&A forum. I understand how confusing and frustrating this can be, especially when the device is plugged in but the battery still drops during heavier use.

Just to clarify the power adapter details, as this part often causes confusion: Surface Power Supply model 1798 delivers 95W to the Surface device (15V / 6.33A). You may sometimes see it referred to as 102W total, but that number includes the small USB‑A charging port on the adapter. The USB port power is separate and doesn’t increase the power delivered to the Surface itself.

For Surface Book 3 models, the power requirements depend on the size and GPU configuration:

• Surface Book 3 13.5‑inch (with NVIDIA discrete GPU) uses Model 1798 (95W).
• Surface Book 3 15‑inch is designed to use the higher‑wattage 120W/127W power supply (Model 1932).

If a 15‑inch Surface Book 3 is used with a 95W adapter (Model 1798), it’s expected that the system may temporarily draw power from the battery during GPU‑intensive tasks like gaming, rendering, or heavy workloads. This typically isn’t related to a Windows issue, but rather how power is supplied under heavy load.

If possible, using the correct higher‑wattage power supply for your model should help prevent the battery from draining while plugged in. As a temporary workaround, lowering graphics settings or avoiding sustained “Best performance” mode during heavy GPU use can also help reduce battery drain.

I hope this helps clarify what you’re seeing.

Please feel free to let me know if you have any other questions. I’m happy to assist further.

If you have extra questions about this answer, please click "Comment".  

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.