How much VRAM does Granite 3.1 20B need?

Granite 3.1 20B requires approximately 0.0 GB VRAM at Q4_K_M quantization with 1K context and 10% overhead. At Q8_0 it needs ~0.0 GB, and at FP16 ~0.0 GB. Use the PCPARTGUIDE VRAM Calculator for exact requirements at any context length and overhead setting.

Can I run Granite 3.1 20B on a consumer GPU?

Yes, Granite 3.1 20B can run on consumer GPUs. At Q4_K_M quantization with moderate context length, it fits on a 24 GB GPU. For best performance, use a 24 GB or larger GPU with at least 8 GB VRAM for reasonable context lengths.

What is Granite 3.1 20B's context window?

Granite 3.1 20B supports a maximum context window of 131,072 tokens. The default context is 4,096 tokens. Larger contexts require proportionally more VRAM for the KV cache — use the VRAM Calculator to estimate exact requirements at your target context length.

What quantization level should I use for Granite 3.1 20B?

For Granite 3.1 20B, start with Q4_K_M (~0.0 GB) if VRAM-limited. Q8_0 offers better quality at ~2× the VRAM. If you have enough VRAM, Q6_K (~1.5× Q4 VRAM) provides a good balance. For models this large, Q3_K_M may be necessary to fit on consumer hardware.

How does Granite 3.1 20B compare to similar models?

Granite 3.1 20B is a 20.0B Dense model from the IBM Granite family. Browse other IBM Granite models on the PCPARTGUIDE directory for comparable alternatives with different parameter counts and VRAM requirements. Use the Model Transparency scores to assess documentation quality and reproducibility.

IBM GraniteDenseApache 2.0

Granite 3.1 20B

Granite 3.1 20B is a dense transformer language model from the IBM Granite family, containing 20B parameters across 52 layers. It supports up to 131K tokens of context with a hidden dimension of 5120 and 8 KV heads for efficient grouped-que…

20.0B

Parameters

128K

Max Context

Dense

Architecture

—

Released

Text

Modality

About Granite 3.1 20B

Enterprise

Technical Specifications

Total Parameters20.0B

ArchitectureDense

Attention TypeGQA (Grouped Query Attention)

Hidden Dimensiond = 5,120

Transformer Layers52

Attention Heads40

KV Headsn_kv = 8

Head Dimensiond_head = 128

Activation FunctionSwiGLU

NormalizationRMSNorm

Position EmbeddingRoPE

System Requirements

Estimated VRAM at 10% overhead for different quantization methods and context sizes.

Quantization	1K ctx	128K ctx
Q4_K_M0.50 B/W ~97% of FP16	10.54Consumer GPU	36.34Datacenter GPU
Q8_01.00 B/W ~100% of FP16	20.88Consumer GPU	46.68Datacenter GPU
F162.00 B/W Reference	41.55Datacenter GPU	67.35Datacenter GPU

Fits 24 GB consumer GPU

Fits 80 GB datacenter GPU

Requires cluster / multi-GPU

Other IBM Granite Models

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Granite 3.1 2B

Params

2.0B

Layers

Context

128K

Granite 3.1 8B

Params

8.0B

Layers

Context

128K

Find the right GPU for Granite 3.1 20B

Use the interactive VRAM Calculator to see exactly how much memory you need at any quantization level, context length, and overhead setting.

Open VRAM Calculator Best GPU Guide VRAM Guide