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HomeCan I run it?Llama 3.1 8BLlama 3.1 8B on an RX 7900 XTX

Yes. Llama 3.1 8B at FP16 needs about 19.5 GB, and the Radeon RX 7900 XTX has 24.0 GB usable at a ~4k context.

Can I run Llama 3.1 8B on an RX 7900 XTX?

Llama 3.1 8B at FP16 needs about 19.5 GB, and the Radeon RX 7900 XTX 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 960 GB/s memory bandwidth. Meta’s widely used 8B instruct model, the default small local chat model for a few years running. These are estimates from our formula, not measured benchmarks.

Quant that fits
FP16 Fits with headroom
Memory needed
19.5 GB at FP16, ~4k context
Usable VRAM
24.0 GB of 24 GB VRAM
Est. tokens/sec
36–51 estimate

Llama-3.1-8B-Instruct · Radeon RX 7900 XTX · Everything this machine runs · Q4 vs Q8 vs FP16

Memory at each quant

QuantNeed vs 24.0 GBVerdict
Q4_K_M6.6 GBQ4Fits
Q8_010.8 GBQ8Fits
FP1619.5 GBFP16Fits

Estimated tokens per second

Estimate: 36–51 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 32k tokens under our KV estimate. Longer chats need more memory for the cache. Figures assume an FP16 KV cache.

Context headroom for Llama 3.1 8B on an RX 7900 XTX at FP16
ContextKV cache (FP16)Total at FP16Verdict
4k0.5 GB19.5 GBFits
8k1.1 GB20.0 GBFits
16k2.1 GB21.1 GBFits
32k4.3 GB23.2 GBTight
64k8.6 GB27.5 GBWon’t fit
128k17.2 GB36.1 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 Llama 3.1 8B

Other models on an RX 7900 XTX

Quick answers

Can I run Llama 3.1 8B on an RX 7900 XTX?
Yes. Llama 3.1 8B at FP16 needs about 19.5 GB, and the Radeon RX 7900 XTX has 24.0 GB usable.
How much VRAM does Llama 3.1 8B need?
About 6.6 GB at Q4_K_M, 10.8 GB at Q8_0 and 19.5 GB at FP16, estimated for a ~4k context.
How fast is Llama 3.1 8B on an RX 7900 XTX?
Our estimate is 36–51 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 32k tokens before the cache pushes the total over usable memory.

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