Gemma 4 12B IT on RTX 5090 D (32GB) — VRAM, KV Cache & Throughput

Gemma 4 12B IT (11.96B total, 11.96B active, Dense GQA) uses 6.63 GiB of 4-bit weights (Q4_K_M), requiring 7.63 GiB total at 8K context and 8 GiB at 32K on RTX 5090 D (~145.6 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
32 GB · 1792 GB/s
Fits with Safe Headroom
Measured GGUF shard size HF config.json ↗
Memory Allocation Breakdown (GiB) 7.63 GiB (8.19 GB) / 32 GiB (24%)
Model Weights: 6.63 GiB KV Cache & State: 0.44 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
7.63 GiB
8.19 GB (decimal)
Usable Hardware Memory
30.4 GiB
32 GB (physical)
Safe Headroom
+22.77 GiB
24% utilization
Est. Decode Throughput
~145.6 tok/s
11.96B active params
Est. Prefill Throughput
~4022 tok/s
4K Prompt TTFT: ~1018 ms
Est. Cost / 1M Tokens
$0.12
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/gemma-4-12b-it-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve google/gemma-4-12B-it \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~1018ms · ~145.6 tok/s)
[Gemma 4 12B IT · 7.63 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 4 12B IT

QLoRA (4b) Fits with Safe Headroom
9.37 GiB
Model Weights: 6.63 GiB · Gradients + Optimizer: 1.67 GiB · Act: 1.07 GiB
Recommended GPU: RTX 4060 Ti 16GB (16GB)
LoRA (16b) Fits with Safe Headroom
26.33 GiB
Model Weights: 22.28 GiB · Gradients + Optimizer: 2.63 GiB · Act: 1.42 GiB
Recommended GPU: Radeon AI PRO R9700 32GB (32GB)
Full BF16 Exceeds Available GPU Memory
93.85 GiB
Model Weights: 22.28 GiB · Gradients + Optimizer: 69.07 GiB · Act: 2.5 GiB
Recommended GPU: Instinct MI300X 192GB (192GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

RTX 5090 D (32GB physical, 30.4 GiB usable) runs 4-bit (Q4_K_M) Gemma 4 12B IT at 8K context using 7.63 GiB with 22.77 GiB of safe headroom (~145.6 tok/s single-stream decode).

KV Cache & Runtime Tuning

Gemma 4 12B IT uses Dense GQA (11.96B total, 11.96B active per token). Moving from 8K to 32K context expands FP16 KV cache from 0.44 GiB to 0.81 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 0.4 GiB at 32K (reducing total VRAM to 7.6 GiB).

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

Gemma 4 12B IT VRAM scaling from 4K to 128K context (4K: 7.57 GiB, 8K: 7.63 GiB, 32K: 8 GiB, 128K: 9.5 GiB) 4K 7.57 GiB (KV 0.38 GiB) 8K 7.63 GiB (KV 0.44 GiB) 32K 8 GiB (KV 0.81 GiB) 128K 9.5 GiB (KV 2.31 GiB) RTX 5090 D (32GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Gemma 4 12B IT @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (RTX 5090 D) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 22.28 GiB 0.44 GiB 23.28 GiB (25 GB) ~47.7 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 11.83 GiB 0.44 GiB 12.83 GiB (13.78 GB) ~86.6 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 9.11 GiB 0.44 GiB 10.11 GiB (10.86 GB) ~109.9 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) 7.84 GiB 0.44 GiB 8.84 GiB (9.49 GB) ~125.7 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) 6.63 GiB 0.44 GiB 7.63 GiB (8.19 GB) ~145.6 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 5.94 GiB 0.44 GiB 6.94 GiB (7.45 GB) ~160.1 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) 5.3 GiB 0.44 GiB 6.3 GiB (6.76 GB) ~176.4 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) 4.34 GiB 0.44 GiB 5.34 GiB (5.73 GB) ~208.1 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size

Technical Specifications & FAQ

Does Gemma 4 12B IT fit on RTX 5090 D (32GB)?

In 4-bit (Q4_K_M) at 8,192 context, Gemma 4 12B IT requires 7.63 GiB total GPU memory (6.63 GiB weights + 0.44 GiB KV cache + 0.56 GiB runtime buffers) against 30.4 GiB usable on RTX 5090 D, delivering ~145.6 tok/s decode.

How much VRAM does Gemma 4 12B IT need at 32K context?

At 32,768 context tokens, Gemma 4 12B IT (Dense GQA) allocates 0.81 GiB for KV cache and state, bringing total 4-bit VRAM to 8 GiB (8.59 GB decimal).

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