Can AMD Radeon RX 7800 XT run gpt-oss-20b?

This page was written and translated automatically by AI and checked by software against its sources, with no human editing. Specifications come from the sources listed; memory requirements and speeds are estimates calculated with published formulas. How we use AI

Fits By llama.cpp’s default load check, gpt-oss-20b fits on AMD Radeon RX 7800 XT at Q8_0 with a context of 8,192 tokens. One card needs 12.9 GiB available for “Fits”.

At Q8_0, the longest context that fits is 78,848 tokens.

“Fits” means llama.cpp's default --fit load check would place all layers on the GPU: our estimate of llama.cpp's buffers, plus its error margin, plus llama.cpp's 1 GiB per-card reserve, is within the memory counted as available. It does not promise that peak memory while generating fits. How results are decided

Values updated Oct 19, 2026 · Calculator

Run profile: llama.cpp, ROCm back end on Linux (AMD discrete GPU), all layers on the GPU, Flash Attention on, micro-batch (-ub) 512, F16 KV cache, context (-c) as shown; “Fits” is judged with llama-server’s default 4 parallel sequences (-np auto, unified KV cache) and “Doesn’t fit” with 1 sequence; idle GPU with no other programs using its memory.

Memory counted as available for “Fits” (C_low): 14.75 GiB per card = 16 GiB nominal − 16 MiB (nominal minus the total that llama.cpp reported for this GPU in public logs) − 1,216 MiB (the largest start-up and runtime use seen in this profile’s public logs), rounded down to a multiple of 64 MiB.

These results apply to the configuration seen in public logs, where llama.cpp reported 16,368 MiB of total memory for this GPU. Settings that reduce usable memory (for example ECC, where the card supports it) are not covered.

Memory used for “Doesn’t fit” (C_high): the full 16 GiB per card. Run profiles and their measurements

Memory needed by quantization and context

Available memory needed for “Fits” (X, GiB per card) and the result on AMD Radeon RX 7800 XT.
Quantization	4,096	8,192	32,768	131,072
Q8_0	12.8 GiB Fits	12.9 GiB Fits	13.5 GiB Fits	16.1 GiB Tight
Q6_K	12.7 GiB Fits	12.8 GiB Fits	13.5 GiB Fits	16.0 GiB Tight
Q5_K_M	12.6 GiB Fits	12.7 GiB Fits	13.3 GiB Fits	15.9 GiB Tight
Q4_K_M	12.5 GiB Fits	12.6 GiB Fits	13.3 GiB Fits	15.8 GiB Tight
Q4_0	12.5 GiB Fits	12.6 GiB Fits	13.2 GiB Fits	15.8 GiB Tight
Q3_K_M	12.5 GiB Fits	12.6 GiB Fits	13.2 GiB Fits	15.8 GiB Tight
Q2_K	12.4 GiB Fits	12.6 GiB Fits	13.2 GiB Fits	15.8 GiB Tight

No speed ceiling is given: the memory bandwidth of AMD Radeon RX 7800 XT is not confirmed by two independent open sources.

Alternatives

Other 16 GB GPUs where gpt-oss-20b fits

Sources

Model page, with every quantization and its files: gpt-oss-20b
GPU page, with each specification and its sources: AMD Radeon RX 7800 XT
Model files on Hugging Face (pinned revisions): openai/gpt-oss-20b@6cee5e8, unsloth/gpt-oss-20b-GGUF@d449b42
Memory size of AMD Radeon RX 7800 XT from: Wikipedia: Radeon RX 7000 series (CC BY-SA 4.0), ROCm documentation gpu-specs.rst (MIT)
Methodology