Can I run clef-flash on a Mac with 48 GB?

Yes

Its published weights (18.8 GB) fit in the 36.0 GB a Mac with 48 GB can use, with room for ≈ 256K tokens of context.

hf download Cloudflare/clef-flash

Files and context on Mac with 48 GB

Each file of clef-flash (and of GGUF versions the site has analyzed), and how much context fits next to it, with the context cache in 16-bit or 8-bit.

clef-flash on other hardware

Popular models that run on Mac with 48 GB

Assumes 75% of the Mac's memory is usable (macOS's default limit for the GPU; it can be raised) and at least 4K tokens of context for one conversation, with the context cache in 16-bit unless noted. Fits leaves at least 20% of that memory for context; Tight leaves less.