FastMetal

Model comparison

GPT-6.1 Sol vs Grok 4.7

Pricing, context window and real answers (September 2026)

GPT-6.1 Sol (OpenAI) and Grok 4.7 (xAI), 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

openai logoGPT-6.1 Solx-ai logoGrok 4.7
ProviderOpenAIxAI
Input (per 1M tokens)¥357.4¥357.4
Output (per 1M tokens)¥1,787¥1,072.2
Typical cost (1,000 in + 500 out tokens × 1,000 calls)¥1,251¥894
Context window1,050,000 tokens500,000 tokens
Release date9/29/20269/21/2026
Input modalitiesfile, image, texttext, image, file
Throughput (p50)——
Arena · overallUnranked#92 · ELO 1,439
Arena · JapaneseUnrankedUnranked
Arena · codingUnranked#92 · ELO 1,488

Prices are FastMetal's yen rates before tax.

Rankings: LMArena leaderboard dataset (lmarena-ai/leaderboard-dataset), CC BY 4.0, snapshot 2026-09-25; category names mapped and ratings rounded by FastMetal.

Which should you pick?

  • On price, Grok 4.7: ¥1,072.2 per 1M output tokens, 40% less than GPT-6.1 Sol.
  • For long documents, GPT-6.1 Sol: a 1,050,000-token context window against 500,000 for Grok 4.7.
  • 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.

GPT-6.1 Sol

“strawberry” is spelled **s-t-r-a-w-b-e-r-r-y**. The letter **r** appears at positions **3, 8, and 9**. So, there are **3 r’s** in “strawberry.”
2.8s88 output tokens

Grok 4.7

The word "strawberry" consists of the letters S-T-R-A-W-B-E-R-R-Y. - The 3rd letter is R. - The 8th letter is R. - The 9th letter is R. This gives a total of 3 R's.
4.7s299 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…

GPT-6.1 Sol

The error means **`users` is `undefined` when `UserList` renders**. Calling `.map()` on `undefined` throws this error. This commonly happens when the parent doesn’t pass the `users` prop, or when data hasn’t finished loading yet. ### Fix: provide a default empty array ```jsx function UserList({ users = [] }) { return ( <ul> {users.map(user => ( <li key={user.id}>{user.name}</li> ))} </ul> ); } ``` This renders an empty list if `users` is omitted or `undefined`. It does **not** handle `null`. ### Check the parent component too Make sure it passes an array: ```jsx <UserList users={users} /> ``` If you’re fetching users asynchronously, initialize the stat…
5.8s306 output tokens

Grok 4.7

The error happens because `users` is `undefined` when `UserList` renders, so calling `.map` on it fails. That usually means the parent rendered `<UserList />` (or `<UserList users={undefined} />`) before data was loaded, or the prop name doesn’t match. **Fix it in the component** so it tolerates a missing list: ```jsx function UserList({ users = [] }) { return ( <ul> {users.map(user => <li key={user.id}>{user.name}</li>)} </ul> ); } ``` Or guard the call: ```jsx function UserList({ users }) { return ( <ul> {(users ?? []).map(user => <li key={user.id}>{user.name}</li>)} </ul> ); } ``` **Also check the parent** so you pass an array once data exists: `…
12.8s393 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):…

GPT-6.1 Sol

The function is short, but its main weakness is that it hides failures: a network error, invalid JSON, and a genuinely empty result all return `[]`. ### Suggested improvements - **Move imports to module scope.** This is conventional and makes dependencies visible. Repeated imports are cached, so the performance benefit is minor. - **Avoid bare `except:`.** It catches everything, including `KeyboardInterrupt` and `SystemExit`, and can hide programming errors. - **Handle HTTP errors explicitly.** `raise_for_status()` provides useful exceptions. Retry transient failures such as timeouts, connection errors, HTTP 429, and HTTP 5xx—not permanent errors such as HTTP 404. - **Don’t sleep after the…
19.0s1094 output tokens

Grok 4.7

## Review The function works for the happy path, but it hides failures, retries the wrong errors, and is harder to read and debug than it needs to be. ### Issues 1. **Imports inside the function** — move them to module level unless you have a strong reason (circular imports, optional dependency). 2. **Bare `except`** — swallows `KeyboardInterrupt`, `SystemExit`, and programming bugs. Catch specific exceptions. 3. **Retries non-retryable failures** — 4xx (except maybe 429) will not succeed on retry. Network errors and 5xx are the usual candidates. 4. **Sleeps after the last attempt** — wastes up to 2 seconds before returning `[]`. 5. **Unused loop variable** and vague names (`r`, `i`). 6.…
22.3s1525 output tokens

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Frequently asked questions

Which is cheaper, GPT-6.1 Sol or Grok 4.7?
Per 1M output tokens, GPT-6.1 Sol is ¥1,787 and Grok 4.7 is ¥1,072.2 on FastMetal (yen, before tax), so Grok 4.7 is cheaper.
How do the context windows of GPT-6.1 Sol and Grok 4.7 compare?
GPT-6.1 Sol takes 1,050,000 tokens; Grok 4.7 takes 500,000.
Can I use GPT-6.1 Sol and Grok 4.7 with the same API key?
Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gpt-6.1-sol" or "grok-4.7" 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 GPT-6.1 Sol and Grok 4.7 from the browser chat and the API. No monthly fee.

Create a free accountTry GPT-6.1 Sol in chatTry Grok 4.7 in chat

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