Question 1

Can I run GPT-OSS 20B on a AMD Radeon RX 7900 XT?

Accepted Answer

Yes — AMD Radeon RX 7900 XT runs GPT-OSS 20B fully on GPU at the Q5_K_M quantization. Full GPU inference — 20 GB VRAM meets the 16.3 GB recommendation.

Question 2

What quantization of GPT-OSS 20B should I use on a AMD Radeon RX 7900 XT?

Accepted Answer

For 20 GB VRAM on the AMD Radeon RX 7900 XT, the Q5_K_M variant is the best fit. Estimated ~55.7 tokens/sec on the Q5_K_M quantization.

Question 3

How fast does GPT-OSS 20B run on AMD Radeon RX 7900 XT?

Accepted Answer

Roughly 55.7 tokens/sec for Q5_K_M. Real speed depends on context length, backend (Ollama, llama.cpp, LM Studio), and KV cache size.

Question 4

What if AMD Radeon RX 7900 XT is not enough for GPT-OSS 20B?

Accepted Answer

Try a smaller quantization variant or run on CPU + RAM with the trade-off of slower generation.

Quantization	File Size	Min VRAM	Rec VRAM	Context	Verdict	Estimated tok/s
Q4_K_M	10 GB	11.5 GB	13 GB	8K / 8K	Full GPU	~64
Q5_K_MBest fit	12.5 GB	14.4 GB	16.3 GB	8K / 8K	Full GPU	~55.7
Q8_0	20 GB	23 GB	26 GB	8K / 8K	Hybrid CPU+GPU	~12
FP16	40 GB	46 GB	52 GB	8K / 8K	Hybrid CPU+GPU	~6

Can I Run GPT-OSS 20B on AMD Radeon RX 7900 XT?

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Every GPT-OSS 20B quantization on AMD Radeon RX 7900 XT