Model comparison

Gemini 3.5 Flash vs LLM-jp-3.1 8x13B instruct4

Pricing, context window and real answers (August 2026)

Gemini 3.5 Flash (Google) and LLM-jp-3.1 8x13B instruct4 (Llm Jp), compared as you can actually call them on FastMetal. Both are served from the same OpenAI-compatible endpoint and API key; switching is a change to the model string.

Specs and pricing

google logoGemini 3.5 FlashLLM-jp-3.1 8x13B instruct4
ProviderGoogleLlm Jp
Input (per 1M tokens)¥268.05¥16
Output (per 1M tokens)¥1,608.3¥79
Typical cost (1,000 in + 500 out tokens × 1,000 calls)¥1,072¥56
Context window1,048,576 tokens4,096 tokens
Release date5/19/20263/21/2026
Input modalitiestext, image, video, file, audiotext
Arena · overall#21 · ELO 1,479Unranked
Arena · Japanese#17 · ELO 1,479Unranked
Arena · coding#51 · ELO 1,508Unranked

Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.

Which should you pick?

  • On price, LLM-jp-3.1 8x13B instruct4: ¥79 per 1M output tokens, 95% less than Gemini 3.5 Flash.
  • For long documents, Gemini 3.5 Flash: a 1,048,576-token context window against 4,096 for LLM-jp-3.1 8x13B instruct4.
  • If in doubt, try both on the same key. Switching is a change to the model string, and each is billed at its own rate.

Real answers to the same prompts

Exactly what the FastMetal gateway returned, side by side. Not benchmark scores: actual output.

Count the number of 'r's in 'strawberry'

Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.

Gemini 3.5 Flash

There are **3** 'r's in the word "strawberry". Here is the step-by-step breakdown of how to count them: 1. **Break the word down into its individual letters:** * 1st letter: **s** * 2nd letter: **t** * 3rd letter: **r** (First 'r') * 4th letter: **a** * 5th letter: **w** * 6th letter: **b** * 7th letter: **e** * 8th letter: **r** (Second 'r') * 9th letter: **r** (Third 'r') * 10th letter: **y** 2. **Identify and count only the 'r's:** * s - t - **r** (1) - a - w - b - e - **r** (2) - **r** (3) - y By counting them as we go through the word, we find a total of **3** 'r's.
4.8s601 output tokens

LLM-jp-3.1 8x13B instruct4

To count the number of 'r's in the word 'strawberry', follow these steps: 1. Identify the word: The word we are examining is 'strawberry'. 2. Understand the task: We need to find and count all occurrences of the letter 'r' in this word. 3. Begin with the first letter: The first letter is 's', which is not 'r', so we move on to the next letter. 4. Proceed to the second letter: The second letter is 't', which is also not 'r', so we continue to the third letter. 5. Reach the third letter: The third letter is 'r'. We have found one 'r'. 6. Continue to the fourth letter: The fourth letter is 'a', which is not 'r', so we move on to the fifth letter. 7. Examine the fifth letter: The fifth letter i…
4.0s400 output tokens

Debug This Error

I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…

Gemini 3.5 Flash

### What is causing this error? The error `TypeError: Cannot read properties of undefined (reading 'map')` means that your `UserList` component is trying to call `.map()` on the `users` variable, but **`users` is currently `undefined`**. This usually happens for one of two reasons: 1. **The parent component forgot to pass the prop:** `<UserList />` was rendered without the `users` attribute. 2. **Asynchronous data fetching:** The parent component fetches the users from an API, but the API request hasn't finished yet when the component first renders, so `users` starts as `undefined`. --- ### How to fix it Here are the three best ways to fix this, depending on how you want your UI to beh…
11.2s1524 output tokens

LLM-jp-3.1 8x13B instruct4

The error TypeError: Cannot read properties of undefined (reading 'map') suggests that the 'users' argument passed to the UserList component is undefined or does not have a 'map' method. The cause of the problem may be that the users variable is not being passed correctly or is not defined in the parent component. Check the props being passed to the UserList component to ensure that they are defined and contain the expected data. To fix the issue, you can add some error handling and debugging to your component. Try logging the users variable to the console to verify that it is not undefined: ```jsx function UserList({ users }) { console.log("Users:", users); if (!users) { return <…
3.0s279 output tokens

Code Review

Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…

Gemini 3.5 Flash

Here is a review of your function, followed by two improved versions (one that keeps your structure but makes it Pythonic, and one production-ready version that uses industry best practices). --- ### Key Areas for Improvement 1. **Imports inside the function:** `import requests` and `import time` should be at the top of the file (PEP 8). Keeping them inside the function slows down execution if the function is called repeatedly. 2. **Bare `except:` clause:** Using `except:` without specifying an exception type is a major anti-pattern. It catches things you don't want to catch, like `KeyboardInterrupt` (Ctrl+C) or `SystemExit`. It should target `requests.RequestException`. 3. **Implicit `Tr…
19.7s2975 output tokens

LLM-jp-3.1 8x13B instruct4

The provided Python function aims to get data from a URL using the requests library, filter out specific items based on their "active" field, and return the result. Here are some suggestions to improve readability, performance, and adherence to best practices: 1. Configure the linter (e.g., flake8 or pylint) to ensure code quality and enforce a consistent coding style. 2. Use type hints to improve readability and maintainability. 3. Use context managers (with statement) for handling requests: 4. Rewrite the function using a more functional programming style: Here's the improved version of the function: ```python import requests import time from typing import List, Dict, Any def get_da…
3.9s406 output tokens

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Frequently asked questions

Which is cheaper, Gemini 3.5 Flash or LLM-jp-3.1 8x13B instruct4?
Per 1M output tokens, Gemini 3.5 Flash is ¥1,608.3 and LLM-jp-3.1 8x13B instruct4 is ¥79 on FastMetal (yen, before tax), so LLM-jp-3.1 8x13B instruct4 is cheaper.
How do the context windows of Gemini 3.5 Flash and LLM-jp-3.1 8x13B instruct4 compare?
Gemini 3.5 Flash takes 1,048,576 tokens; LLM-jp-3.1 8x13B instruct4 takes 4,096.
Can I use Gemini 3.5 Flash and LLM-jp-3.1 8x13B instruct4 with the same API key?
Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gemini-3.5-flash" or "llm-jp-3.1-8x13b-instruct4" as the model. Each is billed at its own rate from the same prepaid balance.

Try both on one API key

Create an account and add credit to call Gemini 3.5 Flash and LLM-jp-3.1 8x13B instruct4 from the browser chat and the API. No monthly fee.

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