07. AMD ROCm Compatibility
Chapter 7 of 20 · 20 min
AMD GPUs offer competitive performance through ROCm (Radeon Open Compute) but require careful compatibility verification.
ROCm-Supported consumer GPUs
| GPU | VRAM | ROCm Support | Notes |
|---|---|---|---|
| RX 6600 | 8GB | ROCm 6.0+ | Entry-level |
| RX 6700 XT | 12GB | ROCm 5.7+ | Good value |
| RX 6800 | 16GB | ROCm 5.4+ | FP16 weakness |
| RX 6900 XT | 16GB | ROCm 5.4+ | Extreme power |
| RX 7900 XT | 20GB | ROCm 6.0+ | RDNA 3 |
| RX 7900 XTX | 24GB | ROCm 6.0+ | Best consumer |
ROCm Installation Complexity
ROCm requires specific driver and library versions:
# Install ROCm on Ubuntu 22.04
sudo apt install rocm-libs rccl amd-opencl
# Verify installation
rocminfo
# Should list available GPUs
# Set GPU visibility
export ROCM_PATH=/opt/rocm
export HSA_OVERRIDE_GFX_VERSION=10.3.0 # For RDNA3 compatibility fix
Performance Comparison: NVIDIA vs AMD
Equivalent tier GPUs comparison:
| Task | RTX 4070 12GB | RX 7900 XT 20GB |
|---|---|---|
| llama.cpp throughput | 100% | 85-90% |
| ROCm supported frameworks | 100% | 60-70% |
| Power efficiency | Better | Worse |
| Software ecosystem | Superior | Adequate |
llama.cpp ROCm Build
# Build llama.cpp with ROCm support
make LLAMA_HIPBLAS=1
# Verify ROCm is detected
./llama-bench -m model.gguf -ngl 99
# Should show "Device: AMD Radeon RX..."
Common ROCm Issues
- Version mismatch: ROCm 6.0 and ROCm 5.7 have different requirements
- Navi driver issues: Some motherboards require PCIe resizing
- Memory fragmentation: Different allocation strategy than CUDA
- Framework support: Not all inference servers support ROCm
EXERCISE
Check the AMD GPU compatibility list for your intended model server (llama.cpp, ollama, text-generation-webui). Identify any compatibility limitations before purchasing.