BBrainOutput

Llama 3.1 405B vs Llama 3.1 70B

Size, context window, license, approximate VRAM and the minimum local hardware each model needs — computed from our catalog and compatibility engine, not benchmarks.

Llama 3.1 405BLlama 3.1 70B
Parameters405B70B
Context window128K tokens128K tokens
LicenseLlama Community LicenseLlama Community License
~VRAM @ 4-bit (Q4_K_M)~230 GB~42 GB
~VRAM @ 8-bit (Q8_0)~410 GB~75 GB
Minimum deviceSupermicro 8x H100 SuperServerNVIDIA RTX A6000
Recommended deviceSupermicro 8x H100 SuperServerSupermicro 8x H100 SuperServer
DeploymentCloudHybrid
CapabilitiesTools, Reasoning, Multilingual, Long contextTools, Reasoning, Multilingual, Long context

Highlighted cells mark the lighter / longer / more permissive side per row, for local deployment. Informational rows have no winner.

Bottom line

Llama 3.1 70B (~70B) is lighter than Llama 3.1 405B (~405B), so it runs on more modest hardware, while Llama 3.1 405B trades a larger footprint for more capacity. At 4-bit, Llama 3.1 70B needs about 42GB versus ~230GB, a meaningful gap when choosing a GPU. Both target a 128K context window. Minimum viable hardware differs: Llama 3.1 405B starts on a Supermicro 8x H100 SuperServer, Llama 3.1 70B on a NVIDIA RTX A6000. Figures are approximate working-set estimates, not benchmarks — verify the exact release before committing hardware.

Pick Llama 3.1 405B if…

Pick Llama 3.1 405B if you have the memory to spare and want the larger model.

Pick Llama 3.1 70B if…

Pick Llama 3.1 70B if you want the lighter footprint and cheaper hardware.

Full profile
Llama 3.1 405B

Datacenter tier — realistically a multi-GPU / multi-node or cloud target even at 4-bit.

Full profile
Llama 3.1 70B

Flagship tier — ~42GB at 4-bit needs a 48GB card, a 64GB+ unified-memory Mac, or multi-GPU.

Run the winner on hardware you control

Pick the model that fits your footprint, then turn the right machine into a private AI Business OS — no per-seat data leaving your premises.