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HomeCan I run it?Qwen3-8BQwen3-8B on an RTX 4090

Yes. Qwen3-8B at FP16 needs about 19.8 GB, and the GeForce RTX 4090 has 24.0 GB usable at a ~4k context.

Can I run Qwen3-8B on an RTX 4090?

Qwen3-8B at FP16 needs about 19.8 GB, and the GeForce RTX 4090 has 24.0 GB usable. That figure is 24 GB of VRAM on the spec sheet, of which 24.0 GB is usable for weights and cache, at 1008 GB/s memory bandwidth. Alibaba’s 8B Qwen3. A strong small dense model, and a common upgrade from older 7B–8B weights. These are estimates from our formula, not measured benchmarks.

Quant that fits
FP16 Fits with headroom
Memory needed
19.8 GB at FP16, ~4k context
Usable VRAM
24.0 GB of 24 GB VRAM
Est. tokens/sec
37–52 estimate

Qwen3-8B · GeForce RTX 4090 · Everything this machine runs · Q4 vs Q8 vs FP16

Memory at each quant

QuantNeed vs 24.0 GBVerdict
Q4_K_M6.7 GBQ4Fits
Q8_011.0 GBQ8Fits
FP1619.8 GBFP16Fits

Estimated tokens per second

Estimate: 37–52 tokens/sec at FP16. This is a bandwidth-derived range, not a bench. Efficiency is a 60–85% GPU band from How we calculate.

Context headroom

At FP16, this machine has headroom out to about 16k tokens under our KV estimate. Longer chats need more memory for the cache. Figures assume an FP16 KV cache.

Context headroom for Qwen3-8B on an RTX 4090 at FP16
ContextKV cache (FP16)Total at FP16Verdict
4k0.6 GB19.8 GBFits
8k1.2 GB20.4 GBFits
16k2.4 GB21.7 GBTight
32k4.8 GB24.1 GBWon’t fit
64k9.7 GB28.9 GBWon’t fit
128k19.3 GB38.6 GBWon’t fit

From the model’s config. Try other sizes in the VRAM calculator or see the context length guide.

What to do instead

Other hardware for Qwen3-8B

Other models on an RTX 4090

Quick answers

Can I run Qwen3-8B on an RTX 4090?
Yes. Qwen3-8B at FP16 needs about 19.8 GB, and the GeForce RTX 4090 has 24.0 GB usable.
How much VRAM does Qwen3-8B need?
About 6.7 GB at Q4_K_M, 11.0 GB at Q8_0 and 19.8 GB at FP16, estimated for a ~4k context.
How fast is Qwen3-8B on an RTX 4090?
Our estimate is 37–52 tokens per second at FP16. It is not a measured benchmark.
What context length can I use?
At FP16, our KV estimate supports up to about 16k tokens before the cache pushes the total over usable memory.

New models, and what they need to run

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