Llama 3.1 8B Instruct VRAM & Memory Requirements

Memory layers in this estimate

Artifact bytes, raw KV, engine extras, and total demand are separate. This is not a runtime trace.

Weight artifact

14.96 GiB (16,060,556,376 bytes)

Raw KV cache

1.00 GiB (1,073,741,824 bytes)

Engine extras / workspace

0.63 GiB–2.53 GiB

Total estimated demand

16.58 GiB–18.49 GiB

Published artifacts

Memory by quantization and context

Concurrent sequences = 1. KV defaults to FP16. The range includes documented runtime extras for the listed engine. These figures use the same core as the interactive calculator.

Raw KV contribution

Standard GQA/MHA raw KV is 2 × layers × kvHeads × headDim × tokens × sequences × bytes per element. This page uses KV heads (8), not query heads (32). Using query heads would overstate this cache by 4×.

• 8,192 tokens, 1 sequence, FP16: 1,073,741,824 bytes (1.00 GiB)
• 32,768 tokens: 4,294,967,296 bytes (4.00 GiB)

Related pages

• KV cache calculator
• 4-bit, 8-bit, and FP16 memory
• File size is not runtime VRAM
• Methodology
• All can-i-run checks

Sources

• Llama 3.1 8B Instruct model card (Meta) — Context length 128k, GQA, Llama 3.1 Community License. Parameters as printed on the card.
• Meta llama-models sku_list.py (architecture arguments) — arch_args dim=4096, n_layers=32, n_heads=32, n_kv_heads=8. head_dim is dim ÷ n_heads = 128 (Meta's reference model derives it that way; sku_list.py has no head_dim key). The Hugging Face config.json is gated (HTTP 401), so it was not read.
• Hugging Face API — sha 0e9e39f249a16976918f6564b8830bc894c89659; gated manual; safetensors.total=8030261248; 4 safetensors siblings.
• Cross-check only: GGUF header of a community conversion (not an official source) — Header read with an HTTP range request on 2026-10-18; it agrees with Meta's numbers: block_count 32, head_count 32, head_count_kv 8, embedding_length 4096, context_length 131072, rope.dimension_count 128. The catalog values above come from Meta, not from this file.
• Hugging Face model page — Gated (manual). Llama 3.1 Community License applies; this page states facts only and does not redistribute the weights.

Assumptions that affect this result

• Requested context is within the recorded native window of 131072 tokens.
• Full-resident weight estimates use total parameters, including inactive MoE experts.
• Weight bytes come from the selected weight files only, not from every file in the repository.
• Download file size is not peak GPU memory. Runtime layout, allocator padding, and KV are extra.
• Counted files: model-00001-of-00004.safetensors, model-00002-of-00004.safetensors, model-00003-of-00004.safetensors, model-00004-of-00004.safetensors.
• Context budget is the number of cached tokens per sequence (prompt plus reserved generation).
• Concurrent sequences share one model replica; weights are not multiplied by sequence count.
• KV dtype is independent of weight quantization unless you change it.

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