{T}
TokenMath.net
Updated 2026-09-22 11:16 UTC
Head-to-Head Specification Battle

Llama 3.1 405B — Together AI vs DeepSeek-V4.1-Reasoner

Side-by-side technical and economic comparison between Meta / Together's Llama 3.1 405B — Together AI and DeepSeek's DeepSeek-V4.1-Reasoner.

Endpoint Availability & Transition Notice

Llama 3.1 405B — Together AI: Classified as a Legacy Reference model (Deprecated on Together AI (Reference)).

Core Technical & Pricing Comparison
MetricLlama 3.1 405B — Together AIDeepSeek-V4.1-ReasonerAdvantage
Provider OrganizationMeta / TogetherDeepSeek
Standard Input / 1M$3.50$0.50DeepSeek-V4.1-Reasoner (86% lower)
Cached Input / 1MNone$0.01DeepSeek-V4.1-Reasoner lower
Output / 1M$3.50$2.50DeepSeek-V4.1-Reasoner lower
Context Window128k256kDeepSeek-V4.1-Reasoner (256k)
Max Generation Tokens4.1k384kDeepSeek-V4.1-Reasoner
Tokenizer FamilyMeta Llama 3 Tiktoken BPE (~128k vocabulary)DeepSeek Byte-Level BPE (102k vocabulary)

Interactive Side-by-Side Cost Simulator

Live Delta
Input Tokens / Req2,500
Output Tokens / Req800
Daily Requests10,000
Llama 3.1 405B — Together AI
$3,465.00 / month
$0.0116 / request
DeepSeek-V4.1-ReasonerLOWER COST
$791.25 / month
$0.00264 / request
Selecting DeepSeek-V4.1-Reasoner saves $2,673.75 / month (77.2% savings) over Llama 3.1 405B — Together AI.

When to Choose Llama 3.1 405B — Together AI

Opt for Llama 3.1 405B — Together AI when your engineering requirements prioritize Meta / Together's ecosystem, specific tokenizer efficiencies (Exact Llama 3 Tokenizer (±2%)), or when your expected prompt-to-completion ratios favor its $3.5/M input rate.

When to Choose DeepSeek-V4.1-Reasoner

Opt for DeepSeek-V4.1-Reasoner when looking for DeepSeek's tooling integration, specific context window depth (256k tokens), or when output generation volume favors its $2.5/M rate.