HARDWARE FIT CHECK • Meta Llama 4 Scout (109B-A17B MoE) + AMD Radeon RX 7900 XT (20GB GDDR6)71.66 GB / 20 GB VRAM

Can I Run Meta Llama 4 Scout (109B-A17B MoE) on AMD Radeon RX 7900 XT (20GB GDDR6)?

Full VRAM footprint analysis, tokens/sec generation benchmark, and copy-paste Ollama & vLLM runtime commands for running Meta Llama 4 Scout (109B-A17B MoE) (109B) on AMD Radeon RX 7900 XT (20GB GDDR6) (20 GB).

✕ OOM71.66 GB (358%)0 t/s

Model & Target Hardware

interactive
Long-Context Codebase Indexing & Multi-Document Analysis
GPU Topology / Quantity:Single GPU / Unified SoC
Meta Llama 4 Scout (109B-A17B MoE) on AMD Radeon RX 7900 XT (20GB GDDR6)

✕ Out of Memory — Exceeds VRAM Capacity

✕ OOM
Required VRAM
71.66 GB
358% of hardware capacity (20 GB)
Est. Decode Speed
0 tok/s
17B active params @ 800 GB/s
Available Headroom
-51.66 GB
Needs +51.66 GB more VRAM
Memory Allocation & Headroom
71.66 GB allocated of 20 GB capacity
358% utilized
Weights: 65.4 GB
KV: (32K): 3.22 GB
Overhead: 3.04 GB
Deficit: -51.66 GB
⚡ Architecture & Throughput Transparency: Single-user decode speed (~0 tok/s) is memory-bandwidth bound at batch size = 1 on AMD Radeon RX 7900 XT (20GB GDDR6) (800 GB/s). Prompt prefill / TTFT (~0 tok/s) is compute-bound and utilizes GPU Tensor cores. Actual latency varies with FlashAttention-2 and runtime engine (Ollama/vLLM/llama.cpp).
OLLAMA_FLASH_ATTENTION=1 OLLAMA_KV_CACHE_TYPE=q8_0 ollama run llama4:scout

Local Hardware Configurations & Pricing

⚠️ Out of VRAM: High-Capacity Hardware Upgrades
High-bandwidth VRAM specs and current market prices
Multi-GPU Rig↑ Upgrade
48 GB VRAM

2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM)

Best price-to-VRAM homelab rig for 70B Q4_K_M & Qwen 3.8 27B Q8

936 GB/s700W TDP
Apple Silicon✓ Fits Model
112 GB VRAM

Apple Mac Studio M4 Max (128GB Unified Memory)

Running Llama 4 Scout 109B & 70B Q8 locally with 128K+ context

546 GB/s145W TDP
Consumer GPU
20 GB VRAM

AMD Radeon RX 7900 XT (20GB GDDR6)

Sub-$700 GPU with 20GB VRAM fitting 14B Q8 and 27B Q4 models

800 GB/s315W TDP

Quantization Precision Matrix

32K ctx • KV: Q8_0
QuantizationWeightsKV CacheTotal VRAMEst. SpeedFit Status
FP1616 bpw218 GB3.22 GB229.6 GB (1148%)0 t/sOOM
Q8_08.5 bpw115.54 GB3.22 GB123.55 GB (618%)0 t/sOOM
Q6_K6.56 bpw89.38 GB3.22 GB96.48 GB (482%)0 t/sOOM
Q5_K_M5.68 bpw77.39 GB3.22 GB84.07 GB (420%)0 t/sOOM
Q4_K_M4.8 bpw65.4 GB3.22 GB71.66 GB (358%)0 t/sOOM
FP44.25 bpw57.77 GB3.22 GB63.76 GB (319%)0 t/sOOM
IQ3_XS3.3 bpw44.69 GB3.22 GB50.22 GB (251%)0 t/sOOM

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FAQ & Reference

Frequently Asked Questions: Meta Llama 4 Scout (109B-A17B MoE) on AMD Radeon RX 7900 XT (20GB GDDR6)

How much VRAM does Meta Llama 4 Scout (109B-A17B MoE) need on AMD Radeon RX 7900 XT (20GB GDDR6)?

At standard 4-bit quantization (Q4_K_M) with 32K context, Meta Llama 4 Scout (109B-A17B MoE) requires 71.66 GB of total VRAM (weights + KV cache + CUDA runtime overhead).

What inference speed will Meta Llama 4 Scout (109B-A17B MoE) achieve on AMD Radeon RX 7900 XT (20GB GDDR6)?

Based on AMD Radeon RX 7900 XT (20GB GDDR6)'s 800 GB/s memory bandwidth, expected decode speed is approximately 0 tokens per second.

Can I expand context beyond 32K tokens?

Each additional 32K tokens of context requires additional KV cache memory. For longer context windows, consider 8-bit or 4-bit KV cache quantization.