InternLM 2.5 20B vs SD 3.5 Medium

Compare InternLM 2.5 20B and SD 3.5 Medium: 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 InternLM 2.5 20B SD 3.5 Medium
CategoryOpen SourceImage
Parameters20B2.5B
Context Window256KN/A
Input Price$0.02/1M tokens$0.003/image/1M tokens
Output Price$0.04/1M tokensN/A/1M tokens
Latency~180ms~2s

Choose InternLM 2.5 20B when:

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

256K context, Strong reasoning, Good multilingual

Choose SD 3.5 Medium when:

  • ✓ General imagery
  • ✓ Batch generation
  • ✓ Prototyping
Key Strengths:

Good quality, Fast, Open weights

Verdict: InternLM 2.5 20B vs SD 3.5 Medium

For cost efficiency, SD 3.5 Medium wins at $0.003/image/1M input tokens. For speed, InternLM 2.5 20B is faster at ~180ms. InternLM 2.5 20B excels at Long context tasks while SD 3.5 Medium is better for General imagery. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

InternLM 2.5 20B costs $0.02/1M input tokens and $0.04/1M output tokens. SD 3.5 Medium costs $0.003/image input and N/A output. SD 3.5 Medium is 6.7x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

InternLM 2.5 20B has a 256K context window with ~180ms latency. SD 3.5 Medium offers N/A context at ~2s. InternLM 2.5 20B has the larger context window.

Best For

InternLM 2.5 20B (Open Source) is optimized for: Long context tasks, Research, Multilingual. SD 3.5 Medium (Image) works best for: General imagery, Batch generation, Prototyping.

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

# Use SD 3.5 Medium
response_b = client.chat.completions.create(
    model="stable-diffusion-3-5-medium",
    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, InternLM 2.5 20B or SD 3.5 Medium?

InternLM 2.5 20B (Open Source, 20B) offers 256K context. SD 3.5 Medium (Image, 2.5B) offers Good quality. Choose InternLM 2.5 20B for Long context tasks or SD 3.5 Medium for General imagery.

How much does InternLM 2.5 20B cost vs SD 3.5 Medium?

InternLM 2.5 20B: $0.02/1M input, $0.04/1M output. SD 3.5 Medium: $0.003/image/1M input, N/A/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 InternLM 2.5 20B and SD 3.5 Medium 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.