Question 1

Can I run GPT-OSS 20B on a AMD Radeon RX 6700 XT?

Accepted Answer

Mostly — AMD Radeon RX 6700 XT runs GPT-OSS 20B (Q4_K_M) with partial GPU offload. Expect slower speeds than a fully fitting card. Partial GPU offload — 12 GB VRAM is above the 11.5 GB minimum but below the 13 GB recommendation. Some layers will spill to RAM.

Question 2

What quantization of GPT-OSS 20B should I use on a AMD Radeon RX 6700 XT?

Accepted Answer

For 12 GB VRAM on the AMD Radeon RX 6700 XT, the Q4_K_M variant is the best fit. Estimated ~21.5 tokens/sec on the Q4_K_M quantization.

Question 3

How fast does GPT-OSS 20B run on AMD Radeon RX 6700 XT?

Accepted Answer

Roughly 21.5 tokens/sec for Q4_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 6700 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_MBest fit	10 GB	11.5 GB	13 GB	8K / 8K	Partial GPU	~21.5
Q5_K_M	12.5 GB	14.4 GB	16.3 GB	8K / 8K	Hybrid CPU+GPU	~9
Q8_0	20 GB	23 GB	26 GB	8K / 8K	Hybrid CPU+GPU	~6
FP16	40 GB	46 GB	52 GB	8K / 8K	Hybrid CPU+GPU	~3

Can I Run GPT-OSS 20B on AMD Radeon RX 6700 XT?

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Every GPT-OSS 20B quantization on AMD Radeon RX 6700 XT