The slowdowns you're getting are most likely CPU-based, not GPU based (assuming you haven't set your Internal Resolution and AA too high). Your CPU is slow for Dolphin. You have an Ultra-low Voltage CPU (hence the U) suffix. It's not designed for power consumption, and it will throttle down to 1.8GHz frequently if you generate too much heat (which Dolphin tends to make CPUs do). In short, your CPU is the bottleneck here because of its low clock.
About your issue with the Nvidia GPU, just ignore whatever Dolphin reports. Follow admin89's laptop performance guide here: https://forums.dolphin-emu.org/Thread-unofficial-laptop-performance-guide I advise you to pay attention to Part 2 only though.
The best thing you can probably do after that is to stop using 4.0. Try the latest development builds at https://dolphin-emu.org/download (4.0-1130 at this time). Recent builds are much faster than the older stable builds. That said, you laptop isn't ideally suited for Dolphin. Aside from running a handful of lightweight games, you'll experience slowdowns in nearly every other game, no matter what you do.
About your issue with the Nvidia GPU, just ignore whatever Dolphin reports. Follow admin89's laptop performance guide here: https://forums.dolphin-emu.org/Thread-unofficial-laptop-performance-guide I advise you to pay attention to Part 2 only though.
The best thing you can probably do after that is to stop using 4.0. Try the latest development builds at https://dolphin-emu.org/download (4.0-1130 at this time). Recent builds are much faster than the older stable builds. That said, you laptop isn't ideally suited for Dolphin. Aside from running a handful of lightweight games, you'll experience slowdowns in nearly every other game, no matter what you do.