Gemini 3.5 Flash vs Meta Llama 3.1 405B Instruct
On provider list prices, Meta Llama 3.1 405B Instruct costs $3.50 per million input tokens against $1.50 for Gemini 3.5 Flash: effectively level. Output is $3.50 against $9 (2.6x). On Allocate both bill at list plus the 7% transaction fee.
Specifications and provider list prices from the Allocate catalog, checked 2026-07-08. Billed price is list plus the 7% transaction fee.
What the numbers say
Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $4,950 a month on Gemini 3.5 Flash and $5,425 on Meta Llama 3.1 405B Instruct at list: a gap of $475.
Gemini 3.5 Flash reads 1M tokens per request against 4K for Meta Llama 3.1 405B Instruct, 244.1x the window. That decides which one can take whole documents without splitting them.
Choose Gemini 3.5 Flash for
- High-volume support and triage
- Document extraction at scale
- Vision and OCR pipelines
Choose Meta Llama 3.1 405B Instruct for
- Open weights you can fine-tune and own
Common questions
Which is cheaper, Gemini 3.5 Flash or Meta Llama 3.1 405B Instruct?
Gemini 3.5 Flash, on this workload shape. At list prices it is $1.50/$9 per million tokens in and out against $3.50/$3.50 for Meta Llama 3.1 405B Instruct. Billed on Allocate: $1.60/$9.63 against $3.75/$3.75, list plus 7%.
Which has the bigger context window?
Gemini 3.5 Flash: 1,000,000 tokens (1M) against 4,096 (4K) for Meta Llama 3.1 405B Instruct.
Can I fine-tune Gemini 3.5 Flash or Meta Llama 3.1 405B Instruct?
Meta Llama 3.1 405B Instruct publishes open weights (Llama community) and can be fine-tuned on your own data. Gemini 3.5 Flash is a closed model served over API; its weights are not available.
Related comparisons
Run the numbers on your workload
Or don’t choose. On Allocate a route name is the contract: point yours at one model today, swap to the other tomorrow, and compare them on your live traffic with per-token metering.