Inception's Mercury 3 diffusion model claims to beat GPT-6 Luna and Claude Haiku 5.5 at a fraction of the wait

Inception says its new language model, Mercury 3, beats GPT-6 Luna and Claude Haiku 5.5 on a range of benchmarks while running four to eight times faster.

In its announcement, the company calls Mercury 3 the most capable diffusion language model released so far.

The speed comes from how the model is built. Models like GPT or Claude write one word at a time, so each new word has to wait for the one before it. Diffusion models are best known from image generation. They first sketch a rough version of the whole answer and then refine it over several passes, generating many words at once. Google's technical report on DiffusionGemma explains the basic idea.

Mercury 3's lead is narrower than the announcement suggests

Inception's own benchmark table tells a more mixed story. Mercury 3 wins eight of 12 tests, with all three models running at medium settings. The gap is widest in instruction following. On IFBench, Mercury 3 scores 76.84 points, 15 more than GPT-6 Luna. It also leads clearly in autonomous coding on SWE-Bench Atlas with 51.08 points, while its rivals reach 33.33 and 32.26.

Claude Haiku 5.5 wins the longer coding test DeepSWE. It's also better at finding information in long texts. GPT-6 Luna edges ahead in two tests from Artificial Analysis. Inception's short overview is more cautious, describing Mercury 3's quality as on par or better.

According to Inception, Mercury 3 generates 1,068 tokens per second on Nvidia GPUs. In the company's comparison, Claude Haiku 5.5 manages about 240 and GPT-6 Luna about 130. No independent tests exist yet.

Inception says Mercury 3 has more than 40 times as many parameters as Mercury 1 but runs just as fast. Performance has also tripled since the small Mercury 1 mini. Inception sees this as a sign that diffusion models reliably improve as they scale, just like standard language models. The exact parameter count remains undisclosed.

Mercury 3 targets apps where small delays add up

Mercury 3's low launch pricing may not last

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