Mixtral 8x7B Instruct on B200 180GB (180GB) — VRAM, KV Cache & Throughput

Mixtral 8x7B Instruct (46.7B total, 12.9B active, Sparse MoE + GQA) uses 26.42 GiB of 4-bit weights (Q4_K_M), requiring 27.98 GiB total at 8K context and 30.98 GiB at 32K on B200 180GB (~240.9 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
180 GB · 8000 GB/s
Fits with Safe Headroom
Config-derived formula HF config.json ↗
Memory Allocation Breakdown (GiB) 27.98 GiB (30.04 GB) / 180 GiB (16%)
Model Weights: 26.42 GiB KV Cache & State: 1 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
27.98 GiB
30.04 GB (decimal)
Usable Hardware Memory
171 GiB
180 GB (physical)
Safe Headroom
+143.02 GiB
16% utilization
Est. Decode Throughput
~240.9 tok/s
12.9B active params
Est. Prefill Throughput
~24000 tok/s
4K Prompt TTFT: ~171 ms
Est. Cost / 1M Tokens
$0.38
Sparse MoE + GQA · Apache-2.0

Recommended Hardware for Current Configuration

Best Single GPU
Radeon AI PRO R9700 32GB (32GB)
~$1,299
Best Value / Used GPU
RTX A6000 (48GB)
~$4,500
Apple Unified Memory
Ryzen AI Max+ 395 128GB
~$1,999
Cloud From
RunPod · $0.33 / hr
1x RTX A6000

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf mistralai/Mixtral-8x7B-Instruct-v0.1:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve mistralai/Mixtral-8x7B-Instruct-v0.1 \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~171ms · ~240.9 tok/s)
[Mixtral 8x7B Instruct · 27.98 GiB] allocated on target GPU. Prefill completed in TTFT window; streaming autoregressive tokens at memory-bandwidth-bound rate...

Cloud GPU Comparison & Rent-vs-Buy TCO

Verified public rates across RunPod, Vast.ai, Vultr, and DigitalOcean.

Verified: 2026-11-04
Purchase break-even
~38.5 months
Est. local power: $6.38 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 1x RTX A6000 (Community Cloud) 48 GB $0.33 / hr $40.13 / mo Per-second Deploy GPU ↗
Vast.ai 1x A100 80GB SXM (Verified Host · SXM4) 80 GB $0.44 / hr $53.75 / mo Spot / On-demand Deploy GPU ↗
Vultr ($300 Free Credit*) 1x L40S 48GB (Dedicated Instance · $300 Credit*) 48 GB $1.67 / hr $203.19 / mo Hourly Deploy GPU ↗
Vultr Cloud GPU 1x L40S 48GB (Dedicated Instance) 48 GB $1.67 / hr $203.19 / mo Hourly Deploy GPU ↗
DigitalOcean 1x RTX 6000 Ada (Dedicated Instance) 48 GB $1.57 / hr $190.91 / mo Per-second Deploy GPU ↗

Rates reflect public listings on the verification date and fluctuate with regional inventory.

Fine-Tuning VRAM Requirements (QLoRA / LoRA / Full) — Mixtral 8x7B Instruct

QLoRA (4b) Fits with Safe Headroom
29.31 GiB
Model Weights: 26.42 GiB · Gradients + Optimizer: 1.81 GiB · Act: 1.08 GiB
Recommended GPU: Radeon AI PRO R9700 32GB (32GB)
LoRA (16b) Fits with Safe Headroom
91.26 GiB
Model Weights: 86.99 GiB · Gradients + Optimizer: 2.84 GiB · Act: 1.43 GiB
Recommended GPU: Instinct MI300X 192GB (192GB)
Full BF16 Exceeds Available GPU Memory
359.18 GiB
Model Weights: 86.99 GiB · Gradients + Optimizer: 269.67 GiB · Act: 2.52 GiB
Recommended GPU: 4x H200 141GB SXM (564GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

B200 180GB (180GB physical, 171 GiB usable) runs 4-bit (Q4_K_M) Mixtral 8x7B Instruct at 8K context using 27.98 GiB with 143.02 GiB of safe headroom (~240.9 tok/s single-stream decode).

KV Cache & Runtime Tuning

Mixtral 8x7B Instruct uses Sparse MoE + GQA (46.7B total, 12.9B active per token). Moving from 8K to 32K context expands FP16 KV cache from 1 GiB to 4 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 2 GiB at 32K (reducing total VRAM to 28.98 GiB).

VRAM Scaling Across Context Windows (4K to 128K, 4-bit Weights)

Mixtral 8x7B Instruct VRAM scaling from 4K to 128K context (4K: 27.48 GiB, 8K: 27.98 GiB, 32K: 30.98 GiB, 128K: 42.98 GiB) 4K 27.48 GiB (KV 0.5 GiB) 8K 27.98 GiB (KV 1 GiB) 32K 30.98 GiB (KV 4 GiB) 128K 42.98 GiB (KV 16 GiB) B200 180GB (180GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Mixtral 8x7B Instruct @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (B200 180GB) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 86.99 GiB 1 GiB 88.55 GiB (95.08 GB) ~118 tok/s Fits with Safe Headroom Instinct MI300X 192GB (192GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 46.21 GiB 1 GiB 47.77 GiB (51.29 GB) ~179.7 tok/s Fits with Safe Headroom RTX PRO 6000 Blackwell (96GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 35.66 GiB 1 GiB 37.22 GiB (39.96 GB) ~207.9 tok/s Fits with Safe Headroom A40 48GB (48GB) Config-derived formula
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 30.96 GiB 1 GiB 32.52 GiB (34.92 GB) ~223.5 tok/s Fits with Safe Headroom A40 48GB (48GB) Config-derived formula
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 26.42 GiB 1 GiB 27.98 GiB (30.04 GB) ~240.9 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Config-derived formula
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 23.14 GiB 1 GiB 24.7 GiB (26.52 GB) ~255.3 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Config-derived formula
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 21.29 GiB 1 GiB 22.85 GiB (24.54 GB) ~264.2 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Config-derived formula
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 15 GiB 1 GiB 16.56 GiB (17.78 GB) ~299.8 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Config-derived formula

Technical Specifications & FAQ

Does Mixtral 8x7B Instruct fit on B200 180GB (180GB)?

In 4-bit (Q4_K_M) at 8,192 context, Mixtral 8x7B Instruct requires 27.98 GiB total GPU memory (26.42 GiB weights + 1 GiB KV cache + 0.56 GiB runtime buffers) against 171 GiB usable on B200 180GB, delivering ~240.9 tok/s decode.

How much VRAM does Mixtral 8x7B Instruct need at 32K context?

At 32,768 context tokens, Mixtral 8x7B Instruct (Sparse MoE + GQA) allocates 4 GiB for KV cache and state, bringing total 4-bit VRAM to 30.98 GiB (33.26 GB decimal).

Evaluate This Model on Other GPUs

Evaluate Other Models on This Hardware