GPT-4.1 vs InternLM 2.5 20B

Compare GPT-4.1 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 GPT-4.1 InternLM 2.5 20B
CategoryFrontierOpen Source
Parameters~1.8T20B
Context Window1M256K
Input Price$0.10/1M tokens$0.02/1M tokens
Output Price$0.30/1M tokens$0.04/1M tokens
Latency~500ms~180ms

Choose GPT-4.1 when:

  • ✓ Complex reports
  • ✓ Code generation
  • ✓ Enterprise workflows
Key Strengths:

1M context, Best instruction following, Best coding

Choose InternLM 2.5 20B when:

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

256K context, Strong reasoning, Good multilingual

Verdict: GPT-4.1 vs InternLM 2.5 20B

For cost efficiency, InternLM 2.5 20B wins at $0.02/1M input tokens. For speed, InternLM 2.5 20B is faster at ~180ms. GPT-4.1 excels at Complex reports 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

GPT-4.1 costs $0.10/1M input tokens and $0.30/1M output tokens. InternLM 2.5 20B costs $0.02 input and $0.04 output. InternLM 2.5 20B is 5.0x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

GPT-4.1 has a 1M context window with ~500ms latency. InternLM 2.5 20B offers 256K context at ~180ms. GPT-4.1 has the larger context window.

Best For

GPT-4.1 (Frontier) is optimized for: Complex reports, Code generation, Enterprise workflows. 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 GPT-4.1
response_a = client.chat.completions.create(
    model="gpt-4-1",
    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"}]
)

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Get API Key Try in Playground

Frequently Asked Questions

Which is better, GPT-4.1 or InternLM 2.5 20B?

GPT-4.1 (Frontier, ~1.8T) offers 1M context. InternLM 2.5 20B (Open Source, 20B) offers 256K context. Choose GPT-4.1 for Complex reports or InternLM 2.5 20B for Long context tasks.

How much does GPT-4.1 cost vs InternLM 2.5 20B?

GPT-4.1: $0.10/1M input, $0.30/1M 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 GPT-4.1 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.