Llama 3.1 8B Instruct on H20 96GB HBM3 (96GB) — VRAM, KV Cache & Throughput

Llama 3.1 8B Instruct (8.03B total, 8.03B active, Dense GQA) uses 4.58 GiB of 4-bit weights (Q4_K_M), requiring 6.14 GiB total at 8K context and 9.14 GiB at 32K on H20 96GB HBM3 (~364 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
96 GB · 4000 GB/s
Fits with Safe Headroom
Measured GGUF shard size HF config.json ↗
Memory Allocation Breakdown (GiB) 6.14 GiB (6.59 GB) / 96 GiB (6%)
Model Weights: 4.58 GiB KV Cache & State: 1 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
6.14 GiB
6.59 GB (decimal)
Usable Hardware Memory
91.2 GiB
96 GB (physical)
Safe Headroom
+85.06 GiB
6% utilization
Est. Decode Throughput
~364 tok/s
8.03B active params
Est. Prefill Throughput
~9584 tok/s
4K Prompt TTFT: ~427 ms
Est. Cost / 1M Tokens
$0.05
Dense GQA · Llama 3.1

Recommended Hardware for Current Configuration

Best Single GPU
RTX 4060 Ti 16GB (16GB)
~$430
Best Value / Used GPU
RTX 3060 12GB (12GB)
~$280
Apple Unified Memory
Ryzen AI Max+ 395 128GB
~$1,999
Cloud From
Vast.ai · $0.06 / hr
1x RTX 3060 12GB

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf unsloth/Llama-3.1-8B-Instruct-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve meta-llama/Llama-3.1-8B-Instruct \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~427ms · ~364 tok/s)
[Llama 3.1 8B Instruct · 6.14 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: 2026-11-05
Purchase break-even
~23.4 months
Est. local power: $3.51 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 1x RTX 5060 Ti 16GB (Community Cloud) 16 GB $0.18 / hr $21.89 / mo Per-second Deploy GPU ↗
Vast.ai 1x RTX 3060 12GB (Verified Host) 12 GB $0.06 / hr $7.42 / 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) — Llama 3.1 8B Instruct

QLoRA (4b) Fits with Safe Headroom
6.86 GiB
Model Weights: 4.58 GiB · Gradients + Optimizer: 1.2 GiB · Act: 1.08 GiB
Recommended GPU: RTX 4060 Ti 16GB (16GB)
LoRA (16b) Fits with Safe Headroom
18.19 GiB
Model Weights: 14.96 GiB · Gradients + Optimizer: 1.8 GiB · Act: 1.43 GiB
Recommended GPU: Arc Pro B60 24GB (24GB)
Full BF16 Fits with Safe Headroom
63.86 GiB
Model Weights: 14.96 GiB · Gradients + Optimizer: 46.38 GiB · Act: 2.52 GiB
Recommended GPU: RTX PRO 6000 Blackwell (96GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

H20 96GB HBM3 (96GB physical, 91.2 GiB usable) runs 4-bit (Q4_K_M) Llama 3.1 8B Instruct at 8K context using 6.14 GiB with 85.06 GiB of safe headroom (~364 tok/s single-stream decode).

KV Cache & Runtime Tuning

Llama 3.1 8B Instruct uses Dense GQA (8.03B total, 8.03B 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 7.14 GiB).

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

Llama 3.1 8B Instruct VRAM scaling from 4K to 128K context (4K: 5.64 GiB, 8K: 6.14 GiB, 32K: 9.14 GiB, 128K: 21.14 GiB) 4K 5.64 GiB (KV 0.5 GiB) 8K 6.14 GiB (KV 1 GiB) 32K 9.14 GiB (KV 4 GiB) 128K 21.14 GiB (KV 16 GiB) H20 96GB HBM3 (96GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Llama 3.1 8B Instruct @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (H20 96GB HBM3) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 14.96 GiB 1 GiB 16.52 GiB (17.74 GB) ~144.2 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 7.95 GiB 1 GiB 9.51 GiB (10.21 GB) ~243.5 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 6.14 GiB 1 GiB 7.7 GiB (8.27 GB) ~296.2 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 5.34 GiB 1 GiB 6.9 GiB (7.41 GB) ~327.4 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 4.58 GiB 1 GiB 6.14 GiB (6.59 GB) ~364 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 4.16 GiB 1 GiB 5.72 GiB (6.14 GB) ~380 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 3.74 GiB 1 GiB 5.3 GiB (5.69 GB) ~380 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 3.16 GiB 1 GiB 4.72 GiB (5.07 GB) ~380 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size

Technical Specifications & FAQ

Does Llama 3.1 8B Instruct fit on H20 96GB HBM3 (96GB)?

In 4-bit (Q4_K_M) at 8,192 context, Llama 3.1 8B Instruct requires 6.14 GiB total GPU memory (4.58 GiB weights + 1 GiB KV cache + 0.56 GiB runtime buffers) against 91.2 GiB usable on H20 96GB HBM3, delivering ~364 tok/s decode.

How much VRAM does Llama 3.1 8B Instruct need at 32K context?

At 32,768 context tokens, Llama 3.1 8B Instruct (Dense GQA) allocates 4 GiB for KV cache and state, bringing total 4-bit VRAM to 9.14 GiB (9.81 GB decimal).

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