Qwen3 4B Instruct 2507 on H20 141GB HBM3e (141GB) — VRAM, KV Cache & Throughput

Qwen3 4B Instruct 2507 (4.02B total, 4.02B active, Dense GQA) uses 2.33 GiB of 4-bit weights (Q4_K_M), requiring 4.02 GiB total at 8K context and 7.39 GiB at 32K on H20 141GB HBM3e (~380 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
141 GB · 4800 GB/s
Fits with Safe Headroom
Measured GGUF shard size HF config.json ↗
Memory Allocation Breakdown (GiB) 4.02 GiB (4.32 GB) / 141 GiB (3%)
Model Weights: 2.33 GiB KV Cache & State: 1.13 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
4.02 GiB
4.32 GB (decimal)
Usable Hardware Memory
133.9 GiB
141 GB (physical)
Safe Headroom
+129.88 GiB
3% utilization
Est. Decode Throughput
~380 tok/s
4.02B active params
Est. Prefill Throughput
~19144 tok/s
4K Prompt TTFT: ~214 ms
Est. Cost / 1M Tokens
$0.04
Dense GQA · Apache-2.0

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/Qwen3-4B-Instruct-2507-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve Qwen/Qwen3-4B-Instruct-2507 \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~214ms · ~380 tok/s)
[Qwen3 4B Instruct 2507 · 4.02 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
~18.5 months
Est. local power: $3.51 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 1x RTX 3090 (Community Cloud) 24 GB $0.22 / hr $26.75 / 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) — Qwen3 4B Instruct 2507

QLoRA (4b) Fits with Safe Headroom
4.56 GiB
Model Weights: 2.33 GiB · Gradients + Optimizer: 1.2 GiB · Act: 1.03 GiB
Recommended GPU: RTX 4060 Ti 16GB (16GB)
LoRA (16b) Fits with Safe Headroom
10.65 GiB
Model Weights: 7.49 GiB · Gradients + Optimizer: 1.8 GiB · Act: 1.36 GiB
Recommended GPU: RTX 4060 Ti 16GB (16GB)
Full BF16 Fits with Safe Headroom
33.11 GiB
Model Weights: 7.49 GiB · Gradients + Optimizer: 23.22 GiB · Act: 2.4 GiB
Recommended GPU: A40 48GB (48GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

H20 141GB HBM3e (141GB physical, 133.9 GiB usable) runs 4-bit (Q4_K_M) Qwen3 4B Instruct 2507 at 8K context using 4.02 GiB with 129.88 GiB of safe headroom (~380 tok/s single-stream decode).

KV Cache & Runtime Tuning

Qwen3 4B Instruct 2507 uses Dense GQA (4.02B total, 4.02B active per token). Moving from 8K to 32K context expands FP16 KV cache from 1.13 GiB to 4.5 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 2.25 GiB at 32K (reducing total VRAM to 5.14 GiB).

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

Qwen3 4B Instruct 2507 VRAM scaling from 4K to 128K context (4K: 3.44 GiB, 8K: 4.02 GiB, 32K: 7.39 GiB, 128K: 20.89 GiB) 4K 3.44 GiB (KV 0.56 GiB) 8K 4.02 GiB (KV 1.13 GiB) 32K 7.39 GiB (KV 4.5 GiB) 128K 20.89 GiB (KV 18 GiB) H20 141GB HBM3e (141GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Qwen3 4B Instruct 2507 @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (H20 141GB HBM3e) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 7.49 GiB 1.13 GiB 9.18 GiB (9.86 GB) ~293.1 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 3.99 GiB 1.13 GiB 5.68 GiB (6.1 GB) ~380 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF Q6_K (6-bit — High Precision) (Q6_K) 3.08 GiB 1.13 GiB 4.77 GiB (5.12 GB) ~380 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) 2.69 GiB 1.13 GiB 4.38 GiB (4.7 GB) ~380 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) 2.33 GiB 1.13 GiB 4.02 GiB (4.32 GB) ~380 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 2.11 GiB 1.13 GiB 3.8 GiB (4.08 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) 1.93 GiB 1.13 GiB 3.62 GiB (3.89 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) 1.58 GiB 1.13 GiB 3.27 GiB (3.51 GB) ~380 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size

Technical Specifications & FAQ

Does Qwen3 4B Instruct 2507 fit on H20 141GB HBM3e (141GB)?

In 4-bit (Q4_K_M) at 8,192 context, Qwen3 4B Instruct 2507 requires 4.02 GiB total GPU memory (2.33 GiB weights + 1.13 GiB KV cache + 0.56 GiB runtime buffers) against 133.9 GiB usable on H20 141GB HBM3e, delivering ~380 tok/s decode.

How much VRAM does Qwen3 4B Instruct 2507 need at 32K context?

At 32,768 context tokens, Qwen3 4B Instruct 2507 (Dense GQA) allocates 4.5 GiB for KV cache and state, bringing total 4-bit VRAM to 7.39 GiB (7.93 GB decimal).

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