HARDWARE FIT CHECK • Mistral Large 2 (123B Instruct) + AMD Radeon RX 7900 XT (20GB GDDR6)83.04 GB / 20 GB VRAM

Can I Run Mistral Large 2 (123B Instruct) 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 Mistral Large 2 (123B Instruct) (123B) on AMD Radeon RX 7900 XT (20GB GDDR6) (20 GB).

✕ OOM83.04 GB (415%)0 t/s

Model & Target Hardware

interactive
High-Precision Reasoning & Multilingual Enterprise Agent Workflows
GPU Topology / Quantity:Single GPU / Unified SoC
Mistral Large 2 (123B Instruct) on AMD Radeon RX 7900 XT (20GB GDDR6)

✕ Out of Memory — Exceeds VRAM Capacity

✕ OOM
Required VRAM
83.04 GB
415% of hardware capacity (20 GB)
Est. Decode Speed
0 tok/s
Dense model @ 800 GB/s
Available Headroom
-63.04 GB
Needs +63.04 GB more VRAM
Memory Allocation & Headroom
83.04 GB allocated of 20 GB capacity
415% utilized
Weights: 73.8 GB
KV: (32K): 5.91 GB
Overhead: 3.33 GB
Deficit: -63.04 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 mistral-large:123b

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 bpw246 GB5.91 GB261.27 GB (1306%)0 t/sOOM
Q8_08.5 bpw130.38 GB5.91 GB141.6 GB (708%)0 t/sOOM
Q6_K6.56 bpw100.86 GB5.91 GB111.05 GB (555%)0 t/sOOM
Q5_K_M5.68 bpw87.33 GB5.91 GB97.05 GB (485%)0 t/sOOM
Q4_K_M4.8 bpw73.8 GB5.91 GB83.04 GB (415%)0 t/sOOM
FP44.25 bpw65.19 GB5.91 GB74.13 GB (371%)0 t/sOOM
IQ3_XS3.3 bpw50.43 GB5.91 GB58.86 GB (294%)0 t/sOOM

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FAQ & Reference

Frequently Asked Questions: Mistral Large 2 (123B Instruct) on AMD Radeon RX 7900 XT (20GB GDDR6)

How much VRAM does Mistral Large 2 (123B Instruct) need on AMD Radeon RX 7900 XT (20GB GDDR6)?

At standard 4-bit quantization (Q4_K_M) with 32K context, Mistral Large 2 (123B Instruct) requires 83.04 GB of total VRAM (weights + KV cache + CUDA runtime overhead).

What inference speed will Mistral Large 2 (123B Instruct) 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.