It pretty bad. Just ask it to quote something like the first paragraph of moby dick (i.e. "call me ishmael...") it barely gets past 5 words before it completely gets it wrong. Even the worst normal 4B models get 3-5 sentences.

That’s because diffusion models struggle with memorizing sequences while it’s essentially what autoregressive models excel at.

I’ve tried to fine tune a diffusion model to memorize an MD5 hash and after days of hacking on it, it failed to completely memorize it. Autoregressive models of any size learn it over <1000 iterations.