Gemma 3 4B IT on RTX 5070 12GB (12GB) — VRAM, KV Cache & Throughput

Gemma 3 4B IT (4.3B total, 4.3B active, Dense GQA) uses 2.7 GiB of 4-bit weights (Q4_K_M), requiring 3.56 GiB total at 8K context and 4.12 GiB at 32K on RTX 5070 12GB (~134 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
12 GB · 672 GB/s
Fits with Safe Headroom
Config-derived formula HF config.json ↗
Memory Allocation Breakdown (GiB) 3.56 GiB (3.82 GB) / 12 GiB (30%)
Model Weights: 2.7 GiB KV Cache & State: 0.3 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
3.56 GiB
3.82 GB (decimal)
Usable Hardware Memory
11.4 GiB
12 GB (physical)
Safe Headroom
+7.84 GiB
30% utilization
Est. Decode Throughput
~134 tok/s
4.3B active params
Est. Prefill Throughput
~3749 tok/s
4K Prompt TTFT: ~1093 ms
Est. Cost / 1M Tokens
$0.13
Dense GQA · Gemma

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/gemma-3-4b-it-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve google/gemma-3-4b-it \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~1093ms · ~134 tok/s)
[Gemma 3 4B IT · 3.56 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) — Gemma 3 4B IT

QLoRA (4b) Fits with Safe Headroom
4.93 GiB
Model Weights: 2.7 GiB · Gradients + Optimizer: 1.2 GiB · Act: 1.03 GiB
Recommended GPU: RTX 4060 Ti 16GB (16GB)
LoRA (16b) Tight Fit (<8% Headroom)
11.17 GiB
Model Weights: 8.01 GiB · Gradients + Optimizer: 1.8 GiB · Act: 1.36 GiB
Recommended GPU: RTX 4060 Ti 16GB (16GB)
Full BF16 Exceeds Available GPU Memory
35.24 GiB
Model Weights: 8.01 GiB · Gradients + Optimizer: 24.83 GiB · Act: 2.4 GiB
Recommended GPU: A40 48GB (48GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

RTX 5070 12GB (12GB physical, 11.4 GiB usable) runs 4-bit (Q4_K_M) Gemma 3 4B IT at 8K context using 3.56 GiB with 7.84 GiB of safe headroom (~134 tok/s single-stream decode).

KV Cache & Runtime Tuning

Gemma 3 4B IT uses Dense GQA (4.3B total, 4.3B active per token). Moving from 8K to 32K context expands FP16 KV cache from 0.3 GiB to 0.86 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 0.43 GiB at 32K (reducing total VRAM to 3.69 GiB).

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

Gemma 3 4B IT VRAM scaling from 4K to 128K context (4K: 3.45 GiB, 8K: 3.56 GiB, 32K: 4.12 GiB, 128K: 6.37 GiB) 4K 3.45 GiB (KV 0.2 GiB) 8K 3.56 GiB (KV 0.3 GiB) 32K 4.12 GiB (KV 0.86 GiB) 128K 6.37 GiB (KV 3.11 GiB) RTX 5070 12GB (12GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Gemma 3 4B IT @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (RTX 5070 12GB) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 8.01 GiB 0.3 GiB 8.87 GiB (9.52 GB) ~49.5 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 4.25 GiB 0.3 GiB 5.11 GiB (5.49 GB) ~89.4 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 3.28 GiB 0.3 GiB 4.14 GiB (4.45 GB) ~113 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 2.98 GiB 0.3 GiB 3.84 GiB (4.12 GB) ~123 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 2.7 GiB 0.3 GiB 3.56 GiB (3.82 GB) ~134 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 2.32 GiB 0.3 GiB 3.18 GiB (3.41 GB) ~152.7 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 2.13 GiB 0.3 GiB 2.99 GiB (3.21 GB) ~164.1 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 1.65 GiB 0.3 GiB 2.51 GiB (2.7 GB) ~202.4 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula

Technical Specifications & FAQ

Does Gemma 3 4B IT fit on RTX 5070 12GB (12GB)?

In 4-bit (Q4_K_M) at 8,192 context, Gemma 3 4B IT requires 3.56 GiB total GPU memory (2.7 GiB weights + 0.3 GiB KV cache + 0.56 GiB runtime buffers) against 11.4 GiB usable on RTX 5070 12GB, delivering ~134 tok/s decode.

How much VRAM does Gemma 3 4B IT need at 32K context?

At 32,768 context tokens, Gemma 3 4B IT (Dense GQA) allocates 0.86 GiB for KV cache and state, bringing total 4-bit VRAM to 4.12 GiB (4.42 GB decimal).

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