Tensorbook performance on battery

I almost exclusively use my Tensorbook plugged in, and it’s great - 4K video, games on max settings, deep learning, all work fine. But today I needed to briefly use battery power and it became essentially useless - both Youtube and local videos at 720p would stutter and freeze, and after a few minutes of use even clicking on the Windows Start button would cause a long delay. As soon as I plug it in again it immediately switches back to normal.

I’ve downloaded the latest GPU and SSD drivers and set all Windows power options to be the same for both plug and battery power, but the problem persists.

Is this normal? Are there any BIOS settings that could affect this? I know performance is compromised when running on battery power, but I’ve never experienced anything like this.

I’m still struggling to fix this. Does anyone know what motherboard is inside the Tensorbook? Where can I find BIOS updates?