Can I run SmolLM2-135M-Instruct on an RTX 4090?

Yes

Its published weights (269 MB) fit in the 21.6 GB an RTX 4090 can use, with room for ≈ 8K tokens of context.

hf download HuggingFaceTB/SmolLM2-135M-Instruct

Files and context on RTX 4090

Each file of SmolLM2-135M-Instruct (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.

SmolLM2-135M-Instruct on other hardware

Popular models that run on RTX 4090

Assumes 90% of the card's memory is usable 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.