Mistral Small 3.1 vs InternLM 2.5 20B

Compare Mistral Small 3.1 and InternLM 2.5 20B: pricing, performance, context window, latency, and best use cases. Side-by-side comparison on XALEN.

Updated 2026-05-21 · By Abhishek Raj · Our methodology

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Feature Mistral Small 3.1 InternLM 2.5 20B
CategoryCompactOpen Source
Parameters24B20B
Context Window128K256K
Input Price$0.02/1M tokens$0.02/1M tokens
Output Price$0.04/1M tokens$0.04/1M tokens
Latency~120ms~180ms

Choose Mistral Small 3.1 when:

  • ✓ Lightweight tasks
  • ✓ Classification
  • ✓ Simple generation
Key Strengths:

128K context, Low cost, Fast

Choose InternLM 2.5 20B when:

  • ✓ Long context tasks
  • ✓ Research
  • ✓ Multilingual
Key Strengths:

256K context, Strong reasoning, Good multilingual

Verdict: Mistral Small 3.1 vs InternLM 2.5 20B

For cost efficiency, InternLM 2.5 20B wins at $0.02/1M input tokens. For speed, Mistral Small 3.1 is faster at ~120ms. Mistral Small 3.1 excels at Lightweight tasks while InternLM 2.5 20B is better for Long context tasks. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

Mistral Small 3.1 costs $0.02/1M input tokens and $0.04/1M output tokens. InternLM 2.5 20B costs $0.02 input and $0.04 output. Both models are similarly priced. XALEN offers batch processing at 50% discount on both models.

Performance & Context

Mistral Small 3.1 has a 128K context window with ~120ms latency. InternLM 2.5 20B offers 256K context at ~180ms. InternLM 2.5 20B has the larger context window.

Best For

Mistral Small 3.1 (Compact) is optimized for: Lightweight tasks, Classification, Simple generation. InternLM 2.5 20B (Open Source) works best for: Long context tasks, Research, Multilingual.

Try Both on XALEN

Both models are available through XALEN's OpenAI-compatible API. Switch between them by changing the model parameter:

from xalen import XALEN

client = XALEN(api_key="xln_test_YOUR_KEY")

# Use Mistral Small 3.1
response_a = client.chat.completions.create(
    model="mistral-small-3-1",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use InternLM 2.5 20B
response_b = client.chat.completions.create(
    model="internlm-2-5-20b",
    messages=[{"role": "user", "content": "Your question here"}]
)

Start Building with XALEN

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Get API Key Try in Playground

Frequently Asked Questions

Which is better, Mistral Small 3.1 or InternLM 2.5 20B?

Mistral Small 3.1 (Compact, 24B) offers 128K context. InternLM 2.5 20B (Open Source, 20B) offers 256K context. Choose Mistral Small 3.1 for Lightweight tasks or InternLM 2.5 20B for Long context tasks.

How much does Mistral Small 3.1 cost vs InternLM 2.5 20B?

Mistral Small 3.1: $0.02/1M input, $0.04/1M output. InternLM 2.5 20B: $0.02/1M input, $0.04/1M output. Both available on XALEN with batch processing at 50% discount.

Can I use both models on XALEN?

Yes. XALEN provides 200+ models through a single OpenAI-compatible API. Switch between Mistral Small 3.1 and InternLM 2.5 20B by changing the model parameter. No code changes needed.

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Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.