Gemma 4 26B-A4B IT on RTX 4090 D (24GB) — VRAM, KV Cache & Throughput

Gemma 4 26B-A4B IT (25.81B total, 3.8B active, Sparse MoE + GQA) uses 15.84 GiB of 4-bit weights (UD-Q4_K_XL), requiring 16.75 GiB total at 8K context and 17.22 GiB at 32K on RTX 4090 D (~139.6 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
24 GB · 1008 GB/s
Fits with Safe Headroom
Measured GGUF shard size HF config.json ↗
Memory Allocation Breakdown (GiB) 16.75 GiB (17.99 GB) / 24 GiB (70%)
Model Weights: 15.84 GiB KV Cache & State: 0.35 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
16.75 GiB
17.99 GB (decimal)
Usable Hardware Memory
22.8 GiB
24 GB (physical)
Safe Headroom
+6.05 GiB
70% utilization
Est. Decode Throughput
~139.6 tok/s
3.8B active params
Est. Prefill Throughput
~9921 tok/s
4K Prompt TTFT: ~413 ms
Est. Cost / 1M Tokens
$0.38
Sparse MoE + GQA · Apache-2.0

Recommended Hardware for Current Configuration

Best Single GPU
Arc Pro B60 24GB (24GB)
~$599
Best Value / Used GPU
RTX 3090 (24GB)
~$750
Apple Unified Memory
Ryzen AI Max+ 395 128GB
~$1,999
Cloud From
Vast.ai · $0.19 / hr
1x RTX 3090

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf unsloth/gemma-4-26B-A4B-it-GGUF:UD-Q4_K_XL \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve google/gemma-4-26B-A4B-it \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~413ms · ~139.6 tok/s)
[Gemma 4 26B-A4B IT · 16.75 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
~26.6 months
Est. local power: $4.26 / 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 3090 (Verified Host) 24 GB $0.19 / hr $22.98 / 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 26B-A4B IT

QLoRA (4b) Fits with Safe Headroom
18.08 GiB
Model Weights: 15.84 GiB · Gradients + Optimizer: 1.2 GiB · Act: 1.04 GiB
Recommended GPU: Arc Pro B60 24GB (24GB)
LoRA (16b) Exceeds Available GPU Memory
51.25 GiB
Model Weights: 48.07 GiB · Gradients + Optimizer: 1.8 GiB · Act: 1.38 GiB
Recommended GPU: RTX PRO 6000 Blackwell (96GB)
Full BF16 Exceeds Available GPU Memory
199.51 GiB
Model Weights: 48.07 GiB · Gradients + Optimizer: 149.02 GiB · Act: 2.42 GiB
Recommended GPU: Instinct MI325X 256GB (256GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

RTX 4090 D (24GB physical, 22.8 GiB usable) runs 4-bit (UD-Q4_K_XL) Gemma 4 26B-A4B IT at 8K context using 16.75 GiB with 6.05 GiB of safe headroom (~139.6 tok/s single-stream decode).

KV Cache & Runtime Tuning

Gemma 4 26B-A4B IT uses Sparse MoE + GQA (25.81B total, 3.8B active per token). Moving from 8K to 32K context expands FP16 KV cache from 0.35 GiB to 0.82 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 0.41 GiB at 32K (reducing total VRAM to 16.81 GiB).

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

Gemma 4 26B-A4B IT VRAM scaling from 4K to 128K context (4K: 16.66 GiB, 8K: 16.75 GiB, 32K: 17.22 GiB, 128K: 19.1 GiB) 4K 16.66 GiB (KV 0.27 GiB) 8K 16.75 GiB (KV 0.35 GiB) 32K 17.22 GiB (KV 0.82 GiB) 128K 19.1 GiB (KV 2.7 GiB) RTX 4090 D (24GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Gemma 4 26B-A4B IT @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (RTX 4090 D) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 48.07 GiB 0.35 GiB 48.98 GiB (52.59 GB) ~11.7 tok/s Exceeds Available GPU Memory RTX PRO 6000 Blackwell (96GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 25.54 GiB 0.35 GiB 26.45 GiB (28.4 GB) ~57.7 tok/s Exceeds Available GPU Memory Radeon AI PRO R9700 32GB (32GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 21.58 GiB 0.35 GiB 22.49 GiB (24.15 GB) ~112.4 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Measured GGUF shard size
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 19.7 GiB 0.35 GiB 20.61 GiB (22.13 GB) ~120.1 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Measured GGUF shard size
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (UD-Q4_K_XL) 15.84 GiB 0.35 GiB 16.75 GiB (17.99 GB) ~139.6 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Measured GGUF shard size
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 12.66 GiB 0.35 GiB 13.57 GiB (14.57 GB) ~161.2 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) 11.85 GiB 0.35 GiB 12.76 GiB (13.7 GB) ~167.8 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) 9.82 GiB 0.35 GiB 10.73 GiB (11.52 GB) ~187.1 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Measured GGUF shard size

Technical Specifications & FAQ

Does Gemma 4 26B-A4B IT fit on RTX 4090 D (24GB)?

In 4-bit (UD-Q4_K_XL) at 8,192 context, Gemma 4 26B-A4B IT requires 16.75 GiB total GPU memory (15.84 GiB weights + 0.35 GiB KV cache + 0.56 GiB runtime buffers) against 22.8 GiB usable on RTX 4090 D, delivering ~139.6 tok/s decode.

How much VRAM does Gemma 4 26B-A4B IT need at 32K context?

At 32,768 context tokens, Gemma 4 26B-A4B IT (Sparse MoE + GQA) allocates 0.82 GiB for KV cache and state, bringing total 4-bit VRAM to 17.22 GiB (18.49 GB decimal).

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