CachyOS Dual GPU Setup - ryzendew/Linux-Tips-and-Tricks GitHub Wiki

CachyOS Dual GPU Setup Guide

This guide covers setting up systems with multiple graphics cards (dual GPU), including NVIDIA + Intel, AMD + Intel, and NVIDIA + AMD configurations. Learn how to switch between GPUs and configure applications to use specific GPUs.

Understanding Dual GPU Systems
NVIDIA + Intel Setup
AMD + Intel Setup
NVIDIA + AMD Setup
Switching Between GPUs
Configuring Applications
Power Management
Troubleshooting

Understanding Dual GPU Systems

What is a Dual GPU System?

A dual GPU system has two graphics processing units:

Dedicated GPU: High-performance card (NVIDIA or AMD)
Integrated GPU: Built into CPU (Intel or AMD)

Common configurations:

NVIDIA + Intel: NVIDIA dedicated + Intel integrated
AMD + Intel: AMD dedicated + Intel integrated
NVIDIA + AMD: Both dedicated (rare, usually workstations)

Why Use Dual GPU?

Benefits:

Power saving: Use integrated GPU for light tasks
Performance: Use dedicated GPU for gaming/rendering
Flexibility: Switch based on workload
Battery life: Better on laptops

Use cases:

Laptops: Switch between power saving and performance
Workstations: Use integrated for display, dedicated for compute
Gaming: Use dedicated GPU for games

How Dual GPU Works

Two main approaches:

PRIME (Linux standard)

One GPU drives display
Applications can use either GPU
Requires manual configuration

NVIDIA Optimus (NVIDIA specific)

Automatic switching
Uses integrated for desktop
Uses NVIDIA for applications
Requires special drivers

NVIDIA + Intel Setup

Overview

NVIDIA + Intel is the most common dual GPU configuration, especially on laptops.

Installation

Step 1: Install NVIDIA drivers

# Use chwd (recommended)
sudo chwd -h -a nvidia

# Or manually
sudo pacman -S nvidia nvidia-utils nvidia-settings

Step 2: Install Intel drivers

# Intel drivers usually included, but ensure installed:
sudo pacman -S mesa vulkan-intel lib32-mesa lib32-vulkan-intel

Step 3: Install PRIME support

# Install PRIME utilities
sudo pacman -S nvidia-prime

Configuration

Step 1: Configure X server (X11)

Edit X server configuration:

sudo nano /etc/X11/xorg.conf.d/nvidia.conf

Add configuration:

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "nvidia"
    Inactive "intel"
EndSection

Section "Device"
    Identifier "nvidia"
    Driver "nvidia"
    BusID "PCI:1:0:0"  # Check with: lspci | grep VGA
EndSection

Section "Screen"
    Identifier "nvidia"
    Device "nvidia"
    Option "AllowEmptyInitialConfiguration"
EndSection

Find your PCI bus ID:

lspci | grep -i vga

What this command does:

lspci: Lists all PCI devices (hardware connected to your motherboard)
PCI: Peripheral Component Interconnect - how hardware connects to your computer
|: Pipe symbol - sends output of first command to second command
grep -i vga: Searches for "vga" (video graphics adapter) in the output
-i: Case-insensitive search (matches VGA, vga, Vga, etc.)
grep: A search tool that finds matching text

Example output you might see:

00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 630 (rev 02)
01:00.0 VGA compatible controller: NVIDIA Corporation GA106 [GeForce RTX 3060] (rev a1)

Understanding the output:

00:02.0: This is the bus ID for Intel graphics
Format: XX:YY.Z where XX=bus, YY=device, Z=function
For X config: Convert to PCI:0:2:0 (remove leading zeros, use colons)
01:00.0: This is the bus ID for NVIDIA graphics
For X config: Convert to PCI:1:0:0

How to convert bus ID format:

lspci shows: 01:00.0
X config needs: PCI:1:0:0
Rule: Remove leading zeros, add "PCI:" prefix, use colons between numbers

In the configuration file:

Use the converted format: BusID "PCI:1:0:0"
This tells X server where to find your NVIDIA card

Step 2: Configure Wayland (if using Wayland)

For GNOME on Wayland:

NVIDIA doesn't work well with Wayland
Consider using X11 or different DE

For KDE on Wayland:

Better NVIDIA support
May need additional configuration

Using NVIDIA GPU

Method 1: Use NVIDIA for all (X11)

# Set NVIDIA as primary
sudo prime-select nvidia

# Log out and back in

Method 2: Use Intel for desktop, NVIDIA for apps

# Set Intel as primary
sudo prime-select intel

# Run apps with NVIDIA
prime-run application-name

Method 3: Use NVIDIA Optimus (automatic switching)

# Install optimus-manager
sudo pacman -S optimus-manager

# Configure
sudo optimus-manager --switch nvidia  # Use NVIDIA
sudo optimus-manager --switch intel   # Use Intel
sudo optimus-manager --switch hybrid  # Hybrid mode

Verifying Configuration

Check which GPU is active:

# Check NVIDIA
nvidia-smi

What this command does:

nvidia-smi: NVIDIA System Management Interface
Shows information about your NVIDIA GPU
Only works if NVIDIA drivers are installed and GPU is active

Example output:

+-----------------------------------------------------------------------------+
| NVIDIA-SMI 535.xx       Driver Version: 535.xx       CUDA Version: 12.2  |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  NVIDIA GeForce ...  Off  | 00000000:01:00.0 On |                  N/A |
|  0%   45C    P8    15W / 170W |    1234MiB / 12288MiB |      0%      Default |
+-----------------------------------------------------------------------------+

Understanding the output:

GPU 0: Your NVIDIA graphics card
Name: Model of your GPU (e.g., GeForce RTX 3060)
Temp: GPU temperature (45°C in example)
Memory-Usage: How much GPU memory is being used
GPU-Util: GPU usage percentage (0% = idle, 100% = fully used)

If you see an error:

NVIDIA-SMI has failed: NVIDIA drivers not installed or GPU not active
No devices were found: NVIDIA GPU not detected
Solution: Install NVIDIA drivers or switch to NVIDIA GPU

# Check Intel
intel_gpu_top

What this command does:

intel_gpu_top: Shows Intel GPU information (like top for CPU, but for Intel GPU)
Shows GPU usage, frequency, and power consumption
Only works if Intel GPU is active

Example output:

intel_gpu_top - 14:45:30
    Render/3D/0    BLT/2    VE/1    Video/0
    RC6: 100%    Freq: 350 MHz

Understanding the output:

Render/3D: 3D graphics usage
BLT: Bit Block Transfer (2D graphics)
VE: Video Engine usage
RC6: Power saving state (100% = in power saving mode)
Freq: GPU frequency (350 MHz = low power mode)

If command not found:

# Install intel-gpu-tools
sudo pacman -S intel-gpu-tools

# Check current GPU
glxinfo | grep "OpenGL renderer"

What this command does:

glxinfo: Shows OpenGL (graphics API) information
OpenGL: A graphics library used by many applications
| grep "OpenGL renderer": Searches for the renderer line
Renderer: The actual GPU being used for graphics

Example output (NVIDIA active):

OpenGL renderer string: NVIDIA GeForce RTX 3060/PCIe/SSE2

Example output (Intel active):

OpenGL renderer string: Mesa Intel(R) UHD Graphics 630 (CML GT2)

Understanding the output:

Shows which GPU is currently being used for graphics
NVIDIA GeForce RTX 3060: NVIDIA GPU is active
Mesa Intel: Intel GPU is active
Mesa: Open-source graphics driver (works with Intel, AMD, some NVIDIA)

If command not found:

# Install mesa-utils
sudo pacman -S mesa-utils

AMD + Intel Setup

Overview

AMD + Intel configuration is less common but works well with open-source drivers.

Installation

Step 1: Install AMD drivers

# AMD open-source drivers
sudo pacman -S mesa vulkan-radeon lib32-mesa lib32-vulkan-radeon

# For newer AMD GPUs
sudo pacman -S mesa vulkan-radeon xf86-video-amdgpu

Step 2: Install Intel drivers

# Intel drivers
sudo pacman -S mesa vulkan-intel lib32-mesa lib32-vulkan-intel

Configuration

AMD + Intel uses PRIME by default:

Usually works automatically
May need manual configuration

Configure X server:

sudo nano /etc/X11/xorg.conf.d/20-amdgpu.conf

Add configuration:

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "amd"
    Inactive "intel"
EndSection

Section "Device"
    Identifier "amd"
    Driver "amdgpu"
    BusID "PCI:1:0:0"  # Check with lspci
EndSection

Section "Device"
    Identifier "intel"
    Driver "modesetting"
    BusID "PCI:0:2:0"  # Check with lspci
EndSection

Using AMD GPU

Run applications with AMD:

# Use DRI_PRIME
DRI_PRIME=1 application-name

# Or use prime-run (if installed)
prime-run application-name

Set AMD as default:

Configure in X server config
Or use environment variables

NVIDIA + AMD Setup

Overview

NVIDIA + AMD is rare, usually found in workstations or high-end systems.

Installation

Install both drivers:

# NVIDIA
sudo pacman -S nvidia nvidia-utils

# AMD
sudo pacman -S mesa vulkan-radeon

Configuration

Configure X server for both:

sudo nano /etc/X11/xorg.conf.d/dual-gpu.conf

Add configuration for both GPUs:

Similar to NVIDIA + Intel setup
Configure each GPU separately
Set primary GPU

Using Specific GPU

Run with NVIDIA:

prime-run application-name

Run with AMD:

DRI_PRIME=1 application-name

Switching Between GPUs

Using chwd

chwd can help switch GPUs:

# Switch to NVIDIA
sudo chwd -h -a nvidia

# Switch to Intel
sudo chwd -h -a intel

# Switch to AMD
sudo chwd -h -a amd

See CachyOS Tools Guide for chwd usage.

Using optimus-manager (NVIDIA)

Install optimus-manager:

sudo pacman -S optimus-manager

Switch GPUs:

# Use NVIDIA
sudo optimus-manager --switch nvidia

# Use Intel
sudo optimus-manager --switch intel

# Hybrid mode
sudo optimus-manager --switch hybrid

After switching:

Log out and back in
Or restart system

Manual Switching

Edit X server configuration:

Change primary GPU in config
Restart X server or log out/in

Configuring Applications

Running Applications with Specific GPU

NVIDIA (with PRIME):

# Run application with NVIDIA
prime-run application-name

# Or
__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia application-name

AMD (with PRIME):

# Run application with AMD
DRI_PRIME=1 application-name

Intel:

# Usually default, but can specify:
DRI_PRIME=0 application-name

Steam/Gaming

Configure Steam to use dedicated GPU:

For NVIDIA:

# Launch Steam with NVIDIA
prime-run steam

# Or set in Steam launch options:
__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia %command%

For AMD:

# Launch Steam with AMD
DRI_PRIME=1 steam

Desktop Environment

GNOME:

May need X11 for NVIDIA
Wayland works better with AMD/Intel

KDE:

Better NVIDIA Wayland support
Can configure GPU selection

i3/Window Managers:

Configure in X server config
Use environment variables

Power Management

Laptop Power Saving

Use integrated GPU for power saving:

# Switch to Intel (lower power)
sudo prime-select intel  # For NVIDIA systems

Benefits:

Lower power consumption
Better battery life
Less heat generation

Use dedicated GPU for performance:

# Switch to NVIDIA/AMD (higher performance)
sudo prime-select nvidia  # For NVIDIA systems

Benefits:

Better performance
Higher frame rates
Better for gaming/rendering

Automatic Switching

optimus-manager can auto-switch:

Configure in optimus-manager settings
Switch based on AC/battery
Switch based on application

Configure auto-switching:

# Edit optimus-manager config
sudo nano /etc/optimus-manager/optimus-manager.conf

Troubleshooting

Problem: Can't Switch GPUs

Solutions:

Check drivers are installed:

# Check NVIDIA
nvidia-smi

# Check AMD
lspci | grep -i amd

Check X server configuration:
```
cat /etc/X11/xorg.conf.d/*.conf
```
Try different switching method:

Try optimus-manager
Try manual configuration
Try chwd

Problem: Applications Use Wrong GPU

Solutions:

Explicitly specify GPU:

# For NVIDIA
prime-run application-name

# For AMD
DRI_PRIME=1 application-name

Check application settings:

Some apps have GPU selection in settings
Check Steam launch options

Verify GPU is working:

# Check NVIDIA
nvidia-smi

# Check which GPU is active
glxinfo | grep "OpenGL renderer"

Problem: Display Not Working

Solutions:

Check X server logs:

cat /var/log/Xorg.0.log | grep -i error

Try different GPU:

# Switch to integrated
sudo prime-select intel

Check cables:

Ensure monitor is connected
Try different ports

Problem: Performance Issues

Solutions:

Verify correct GPU is being used:
```
glxinfo | grep "OpenGL renderer"
```
Check drivers are up to date:
```
sudo pacman -Syu
```
Check power settings:

Ensure not in power-saving mode
Check CPU/GPU frequencies

Additional Resources

CachyOS Tools Guide - Using chwd for hardware
CachyOS Performance Guide - Performance optimization
Arch Linux Wiki - PRIME: https://wiki.archlinux.org/title/PRIME
Arch Linux Wiki - NVIDIA: https://wiki.archlinux.org/title/NVIDIA
Arch Linux Wiki - AMD: https://wiki.archlinux.org/title/AMDGPU

Summary

This guide covered:

Understanding dual GPU systems - What they are and why use them
NVIDIA + Intel setup - Most common configuration
AMD + Intel setup - Open-source friendly
NVIDIA + AMD setup - Workstation configuration
Switching between GPUs - How to change active GPU
Configuring applications - Running apps with specific GPU
Power management - Optimizing for battery/performance
Troubleshooting - Common issues and solutions

Key Takeaways:

Dual GPU systems offer flexibility and power savings
NVIDIA + Intel is most common (especially laptops)
Use PRIME for switching between GPUs
Use optimus-manager for automatic switching (NVIDIA)
Configure applications to use specific GPUs
Balance between power saving and performance

This guide is based on the CachyOS Wiki and expanded with detailed explanations for beginners. For the most up-to-date dual GPU information, always refer to the official CachyOS documentation.

CachyOS Dual GPU Setup - ryzendew/Linux-Tips-and-Tricks GitHub Wiki

CachyOS Dual GPU Setup Guide

Table of Contents

Understanding Dual GPU Systems

What is a Dual GPU System?

Why Use Dual GPU?

How Dual GPU Works

NVIDIA + Intel Setup

Overview

Installation

Configuration

Using NVIDIA GPU

Verifying Configuration

AMD + Intel Setup

Overview

Installation

Configuration

Using AMD GPU

NVIDIA + AMD Setup

Overview

Installation

Configuration

Using Specific GPU

Switching Between GPUs

Using chwd

Using optimus-manager (NVIDIA)

Manual Switching

Configuring Applications

Running Applications with Specific GPU

Steam/Gaming

Desktop Environment

Power Management

Laptop Power Saving

Automatic Switching

Troubleshooting

Problem: Can't Switch GPUs

Problem: Applications Use Wrong GPU

Problem: Display Not Working

Problem: Performance Issues

Additional Resources

Summary