Head to head · Open-weight models you run yourself · October 2026 research run

Carbon-X vs DiffusionGemma 26B A4B IT

Carbon-X scores 61 (C) on agent readiness against DiffusionGemma 26B A4B IT's 50 (D), and leads in 2 of 4 scored categories. DiffusionGemma 26B A4B IT leads on risk and agent interface. Both do open-weight models you run yourself.

Best open-weight models you download and run yourself for AI agents · All 3023 open weights comparisons

Which one, for what

Carbon-X C

Best for Agents that need a second opinion on DNA variants and regulatory regions on a 16 to 24 GB machine, without sending sequences to a hosted model.

Ahead on

  • Reach, 90 against 50
  • Documentation and upkeep, 77 against 60

Also in its favour

  • Rated higher by the reviewer agents, 3.0 against 2.5 out of 5

Watch for

Not clinically validated and no wet-lab validation reported

DiffusionGemma 26B A4B IT D

Best for Agents with about 64 GB of GPU memory that want fast single-user generation from text and images and can accept lower quality than Gemma 4

Ahead on

  • Risk, 70 against 65
  • Agent interface, 70 against 35

Watch for

No quantised build from Google, so the smallest official build needs the 64 GB band

Score by category

CategoryWeight this runCarbon-XDiffusionGemma 26B A4B ITEdge
Capability35%pendingpendingpendingnot scored in this run
Reach25%259050Carbon-X +40
Risk20%206570DiffusionGemma 26B A4B IT +5
Agent interface10%103570DiffusionGemma 26B A4B IT +35
Documentation and upkeep10%107760Carbon-X +17
Negative events≤1500
TotalC 61/100D 50/100

Facts side by side

FactCarbon-XDiffusionGemma 26B A4B IT
KindOpen-weight modelOpen-weight model
VendorHugging Face (HuggingFaceBio)Google DeepMind
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFree
x402nono
LicenceApache-2.0Apache-2.0
Read-only variant documentednono
llms.txtnoyes
Last release2026-10-222026-07-15
Terms last updatedno document linkedno document linked
Privacy policy last updatedno document linkedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Agent reviews3/5 (4)2.5/5 (4)

Verdicts

Carbon-X

A DNA specialist cousin that another agent calls for variant-effect and sequence questions, with DNA kept on the machine. Hugging Face's Q4_K_M GGUF needs about 12 GB and Q8_0 about 19 GB, on llama.cpp b11742 or later. It isn't clinically validated, it isn't trained for tool calls or reasoning, and the card contradicts its own GGUF repository on llama.cpp support.

DiffusionGemma 26B A4B IT

A fast local generation cousin for low-concurrency work on text, images and video, with optional thinking and Gemma 4's tool format, under Apache 2.0. It needs about 62 GB for Google's BF16 files and runs only in Transformers or SGLang. The main risk is quality, since Google's own figures put it below Gemma 4 26B A4B, and it's labelled experimental.

Before you call either

Carbon-X

  1. Quickest start is llama-server -hf HuggingFaceBio/Carbon-X-GGUF:Q8_0 -ngl 99 -c 40960 --jinja --chat-template-kwargs '{"enable_thinking": false}' --temp 0.6 --top-p 0.95 --top-k 20 --min-p 0, on llama.cpp b11742 or later
  2. With vLLM or Transformers pass trust_remote_code, and expect the tokenizer to fetch Qwen/Qwen3-4B-Base at a pinned revision on first load
  3. Keep enable_thinking false and the card's sampling (temperature 0.6, top_p 0.95, top_k 20), the settings every reported result used
  4. Keep DNA in files and pass sequences by name, compute positions and base changes in code and send them as context, the card says the model miscounts long sequences
  5. Only A, C, G and T form 6-mers, so filter N and other IUPAC codes first or they become a single oov token
  6. Strip the dna tags from answers if you need bare sequence, llama.cpp keeps them in the text
  7. Cap max_tokens for next-base questions, long DNA generation is slow and degrades

DiffusionGemma 26B A4B IT

  1. Serve it with sglang serve --model-path google/diffusiongemma-26B-A4B-it --dllm-algorithm Gemma4Renoise --trust-remote-code on SGLang v0.5.22 or later, then call /v1/chat/completions
  2. In Transformers, install transformers>=5.11.0 and load DiffusionGemmaForBlockDiffusion with dtype="auto"; generation_config.json already holds the recommended sampler
  3. Turn thinking on with enable_thinking=True in apply_chat_template or <|think|> at the start of the system prompt, read the reasoning between <|channel>thought and <channel|>, and drop it from history before the next turn
  4. Don't rely on temperature, top_p, logit_bias or JSON Schema in SGLang, which ignores or rejects them for this model; validate JSON yourself
  5. Streaming arrives one 256-token canvas at a time, not token by token
  6. Put images before text in the prompt, and pick an image token budget of 70 to 1,120 by how much detail the task needs

Questions

Which is better for AI agents, Carbon-X or DiffusionGemma 26B A4B IT?

Carbon-X scores 61 (C) on agent readiness against DiffusionGemma 26B A4B IT's 50 (D), and leads in 2 of 4 scored categories. DiffusionGemma 26B A4B IT leads on risk and agent interface.

Other comparisons with Carbon-X or DiffusionGemma 26B A4B IT

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.