BIOS Configuration Overview

Proper BIOS configuration is crucial for optimal Proxmox VE performance and successful GPU passthrough. This guide covers essential settings for modern systems.

Essential BIOS Settings

Virtualization Technology

Intel Systems:

• Intel VT-x: Enable CPU virtualization
• Intel VT-d: Enable I/O virtualization for device passthrough
• VMX: Virtual Machine Extensions (usually enabled with VT-x)

AMD Systems:

• AMD-V: Enable CPU virtualization (also called SVM)
• IOMMU: Enable I/O Memory Management Unit
• NX Bit: No-Execute bit protection

Memory Configuration

Above 4G Decoding: Enabled
Resize BAR Support: Enabled (if available)
Memory Remap: Enabled
64-bit PCI Resources: Enabled

Boot Configuration

• Boot Mode: UEFI (recommended over Legacy)
• Secure Boot: Disabled (for custom kernels)
• Fast Boot: Disabled (for troubleshooting)
• CSM Support: Disabled (when using UEFI)

IOMMU Configuration

IOMMU (Input-Output Memory Management Unit) is essential for GPU passthrough:

Intel VT-d Setup

1. Enable Intel VT-d in BIOS
2. Verify support: dmesg | grep -i "DMAR\|IOMMU"
3. Add kernel parameter: intel_iommu=on

AMD IOMMU Setup

1. Enable AMD IOMMU in BIOS
2. Verify support: dmesg | grep -i "AMD-Vi\|IOMMU"
3. Add kernel parameter: amd_iommu=on

GPU-Specific Settings

For GPU Passthrough

• Primary Graphics Adapter: Set to integrated or specific GPU
• Above 4G Decoding: Essential for modern GPUs
• Resize BAR: Improves GPU performance (RTX 30/40 series)
• PCIe Gen: Set to highest supported (Gen 4/5)

Multi-GPU Configurations

• Multi-Monitor Support: Enabled
• IGD Multi-Monitor: Enabled (for Intel integrated graphics)
• PCIe Slot Configuration: Set all slots to x16 or optimal distribution

Power Management

CPU Settings

• C-States: Enabled for power efficiency
• P-States: Enabled for dynamic frequency scaling
• Turbo Boost: Enabled for performance

PCIe Power Management

• ASPM: Auto or Disabled (disable if having stability issues)
• PCIe Power Management: Enabled
• Runtime D3: Enabled for supported devices

Validation Steps

After configuring BIOS settings:

1. Verify Virtualization: Check if VT-x/AMD-V is enabled
2. Confirm IOMMU: Ensure IOMMU groups are properly configured
3. Test GPU Detection: Verify GPUs are detected and grouped correctly
4. Performance Test: Run baseline performance tests

Use our Intel Virtualization Settings and AMD Virtualization Settings guides for vendor-specific configurations.