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// RUN — FITS
Can the NVIDIA GeForce RTX 4090 run NeMO Megatron GPT 20B?
Yes — here's how fast and up to what context, with real measured numbers.
NeMO Megatron GPT 20B on the NVIDIA GeForce RTX 4090
| Quant | Fits? | Max context | Speed | Beyond context |
|---|---|---|---|---|
| FP16 | no | — | — | — |
| Q8 | yes | 2k | 36.8-43.8 t/s | ~1.5-1.7 (slow) |
| Q4 | yes | 36k | 65.7-78.3 t/s | ~2.6-3.1 (slow) |
Estimate (memory-bound). Beyond "max context" the KV cache spills to system RAM offload (depends on your system RAM) and speed drops to the "beyond" figure.
FAQ
Can the NVIDIA GeForce RTX 4090 run NeMO Megatron GPT 20B?▶
Yes. At Q4 it generates ~65.7-78.3 tok/s and fits up to 36k context; beyond that it spills to system RAM offload (depends on your system RAM) and slows to ~2.6-3.1 tok/s.
How much context fits?▶
At Q4, up to about 36k tokens stay in fast memory; longer context spills to system RAM offload (depends on your system RAM) and throughput collapses.