GPU performance is very low on Ubuntu installed on a laptop.

Introduction

I'm having trouble with the GPU speed on Linux installed on xps17.

I have two SSDs set up on my XPS, with SSD1 has still Windows and Linux installed on SSD2.

The GPU is performing well on Windows, but on Linux, the GPU performance is very slow.

The Linux distributions we tried
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 20.10
- Manjaro 20.1
All of them have the same phenomenon (lower GPU performance).

NVIDIA driver version
Windows
- 456.81

Ubuntu
- nvidia-driver-440
- nvidia-driver-450
- nvidia-driver-455
I have tried the following.
The same phenomenon (lower GPU performance) is happening in all of them.

Benchmark 1
GFXBench(Car chase / Resolution 3840x2400)
- Windows (with RTX 2060) About 52 fps
- Linux (with RTX 2060) About 15 fps　
- Linux (with Intel iGPU) About 6 fps

Benchmark 2
Cuda sample(nbody) *cuda version is 11.1
- Windows(when using RTX 2060) About 3000 GFlops.
- Linux (with RTX 2060) About 600 GFlops

prime GPU check

$ glxinfo | grep renderer
OpenGL renderer string: GeForce RTX 2060 with Max-Q Design/PCIe/SSE2

I'd be glad to know if you can find a cause or a solution.