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CachyOS Dual GPU Setup

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Mattscreative edited this page Dec 5, 2025 · 2 revisions

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.

Table of Contents

  1. Understanding Dual GPU Systems
  2. NVIDIA + Intel Setup
  3. AMD + Intel Setup
  4. NVIDIA + AMD Setup
  5. Switching Between GPUs
  6. Configuring Applications
  7. Power Management
  8. 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:

  1. PRIME (Linux standard)
  • One GPU drives display
  • Applications can use either GPU
  • Requires manual configuration
  1. 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:

  1. Check drivers are installed:

    # Check NVIDIA
nvidia-smi

# Check AMD
lspci | grep -i amd

  2. Check X server configuration:

    cat /etc/X11/xorg.conf.d/*.conf

  3. Try different switching method:

  • Try optimus-manager
  • Try manual configuration
  • Try chwd

Problem: Applications Use Wrong GPU

Solutions:

  1. Explicitly specify GPU:

    # For NVIDIA
prime-run application-name

# For AMD
DRI_PRIME=1 application-name

  2. Check application settings:

  • Some apps have GPU selection in settings
  • Check Steam launch options
  1. Verify GPU is working: 
    # Check NVIDIA
nvidia-smi

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

Problem: Display Not Working

Solutions:

  1. Check X server logs:

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

  2. Try different GPU:

    # Switch to integrated
sudo prime-select intel

  3. Check cables:

  • Ensure monitor is connected
  • Try different ports

Problem: Performance Issues

Solutions:

  1. Verify correct GPU is being used:

    glxinfo | grep "OpenGL renderer"

  2. Check drivers are up to date:

    sudo pacman -Syu

  3. Check power settings:

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

Additional Resources

Summary

This guide covered:

  1. Understanding dual GPU systems - What they are and why use them
  2. NVIDIA + Intel setup - Most common configuration
  3. AMD + Intel setup - Open-source friendly
  4. NVIDIA + AMD setup - Workstation configuration
  5. Switching between GPUs - How to change active GPU
  6. Configuring applications - Running apps with specific GPU
  7. Power management - Optimizing for battery/performance
  8. 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.

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