Can I run Qwen3.5-9B-MLX-8bit on an RTX 4090?

Yes

Its published weights (10.4 GB) fit in the 21.6 GB an RTX 4090 can use, with room for ≈ 256K tokens of context.

Full analysis of Qwen3.5-9B-MLX-8bit Everything that runs on RTX 4090 Get the weights on Hugging Face

hf download lmstudio-community/Qwen3.5-9B-MLX-8bit

Files and context on RTX 4090

Each file of Qwen3.5-9B-MLX-8bit (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.

File	Size	On RTX 4090	Context (16-bit)	Context (8-bit)
As published	10.4 GB	Fits	256K	256K
4-bit (estimate)	5.29 GB	Fits	256K	256K

Qwen3.5-9B-MLX-8bit on other hardware

NVIDIA H100Yes
RTX 5090Yes
RTX 4090Yes
RTX 3090Yes
RTX 5060 Ti 16 GBYes
RTX 3060 12 GBYes, just
RTX 4060Probably, at 4-bit
Mac with 32 GBYes
Mac with 64 GBYes
Mac with 128 GBYes

Popular models that run on RTX 4090

Qwen3-0.6BQwen · 752M
Qwen3-VL-8B-InstructQwen · 8.77B
gpt2openai-community · 137M
Qwen3-8BQwen · 8.19B
Qwen3-Coder-30B-A3B-Instruct-GGUFunsloth · 30.5B
Qwen2.5-7B-InstructQwen · 7.62B
Qwen3.5-9BQwen · 9.65B
Qwen2.5-0.5B-InstructQwen · 494M

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.