Can I Run Nemotron Cascade 2 on RTX 4090 Desktop (24 GB VRAM, 64 GB RAM)?

Written by Jakub Rusinowski · Last updated March 15, 2026

Yes, but it is tight

Yes, but it is tight — Nemotron Cascade 2 30B at Q5_K_M needs about 23.8 GB of the 24 GB usable on RTX 4090 Desktop (24 GB VRAM, 64 GB RAM), leaving only ~0.2 GB before the runtime starts swapping. Expect ~31.7 tok/s (estimated), with room for about 8,192 tokens of context.

Confidence: low · Recommended quantization: Q5_K_M · Estimated speed: ~31.7 tok/s

RTX 4090 Desktop (24 GB VRAM, 64 GB RAM) — what it gives a model

Usable memory for models	24 GB
Memory bandwidth	1008 GB/s
Form factor	Desktop
Operating system	Windows or Linux
Memory upgradeable	Yes

Nemotron Cascade 2 on RTX 4090 Desktop (24 GB VRAM, 64 GB RAM): memory by quantization

Quant	Memory needed	Fits 24 GB?	Max context	Est. speed	Download
F16	62.6 GB	✗ No	—	—	60 GB
Q8_0	34.5 GB	✗ No	—	—	31.9 GB
Q6_K	27.2 GB	✗ No	—	—	24.6 GB
Q5_K_M	23.8 GB	✓ Yes	8K	~31.7 tok/s	21.3 GB
Q4_K_M	20.7 GB	✓ Yes	16K	~36.5 tok/s	18.1 GB
Q3_K_M	15.4 GB	✓ Yes	32K	~49.2 tok/s	12.8 GB
Q2_K	12.4 GB	✓ Yes	32K	~60.7 tok/s	9.9 GB

Which Nemotron Cascade 2 sizes fit

Variant	Needs at Q4_K_M	Fits?	Est. speed
Nemotron Cascade 2 70B	45.4 GB	✗ Too large	—
Nemotron Cascade 2 30B	20.7 GB	✓ Fits	~36.5 tok/s

What to watch out for

Only ~0.2 GB of headroom at Q5_K_M: a longer context or a second application can push this into swapping.
1 larger variant of Nemotron Cascade 2 does not fit and would need CPU offload or different hardware.
This model does not publish its full attention configuration, so the KV-cache share of these figures is inferred from its parameter count rather than computed exactly.

RTX 4090 desktop limitations

24 GB is the sweet spot for 27–32B models at Q4; 70B needs offload or a second card.

Recommended setup

Ollama or llama.cpp (CUDA/ROCm) — vLLM if you need concurrent serving

How these numbers are calculated

Memory need = quantized weights + KV cache at 8,192 tokens (f16) + 0.8 GB runtime overhead.
24 GB of VRAM on the NVIDIA GeForce RTX 4090 at 1008 GB/s.
64 GB of system RAM available for CPU offload when a model exceeds VRAM.
Throughput is a memory-bandwidth roofline estimate, not a measurement. It is labelled "estimated" everywhere it appears.
KV cache is inferred from the parameter count because this model does not publish its full attention configuration.

FAQ