Llama 3.1 8B needs ~9.7 GB VRAM. RX 7900 XT 20GB has 20.0 GB. With Q4_K_M quantization, expect ~98 tok/s.
Operating mode
Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.
Current mode
Balanced
Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.
Select quantization to explore
Fit status
Runs well
Decode
105.7 tok/s
TTFT
1831 ms
Safe context
100K
Memory
9.7 GB / 20.0 GB
This setup is broadly balanced for this model.
No major red flags
This recommendation has enough memory headroom and acceptable estimated speed for the selected workload.
| Workload | Grade | Fit | Decode | TTFT | Context |
|---|---|---|---|---|---|
| Chat | A | Runs well | 105.7 tok/s | 999 ms | 100K |
| Coding | A | Runs well | 98.4 tok/s | 1968 ms | 100K |
| Agentic Coding | A | Runs well | 105.7 tok/s | 2663 ms | 100K |
| Reasoning | A | Runs well | 105.7 tok/s | 2164 ms | 100K |
| RAG | A | Runs well | 105.7 tok/s | 3329 ms | 100K |
How Llama 3.1 8B (8B params) fits at each quantization level on RX 7900 XT 20GB (20.0 GB usable).
| Quant | Bits | VRAM | Quality | Fit |
|---|---|---|---|---|
Q2_K | 2 | 3.1 GB | Low | B67 |
Q3_K_S | 3 | 3.9 GB | Low | B67 |
NVFP4 | 4 |
Copy-paste commands to run Llama 3.1 8B on your machine.
Run
ollama run llama3.1Your hardware
| Model | Params | Grade | Decode | Capabilities |
|---|---|---|---|---|
| 30.5B | A | 40.7 tok/s | ||
| 27B | A | 18.3 tok/s |
Yes, RX 7900 XT 20GB can run Llama 3.1 8B with a A grade (Runs well). Expected decode speed: 98.4 tok/s.
Llama 3.1 8B (8B parameters) requires approximately 9.7 GB of memory with Q4_K_M quantization.
The recommended quantization for Llama 3.1 8B is Q4_K_M, which balances quality and memory efficiency.
On RX 7900 XT 20GB, Llama 3.1 8B achieves approximately 98.4 tokens per second decode speed with a time-to-first-token of 1968ms using Q4_K_M quantization.
For coding workloads, Llama 3.1 8B on RX 7900 XT 20GB receives a A grade with 98.4 tok/s and 100K context.
On RX 7900 XT 20GB, Llama 3.1 8B can safely use up to 100K tokens of context. The model's official context limit is 128K, but available memory constrains the safe maximum.
Paste this snippet into any page to show a live fit card.
<iframe src="https://willitrunai.com/embed/llama-3.1-8b-on-rx-7900-xt-20gb" width="400" height="180" frameborder="0" style="border:none;border-radius:12px;overflow:hidden;" title="Will It Run AI — fit result"></iframe>
Preview:
| Medium |
| B67 |
Q4_K_M | 4 | 4.9 GB | Medium | B68 |
Q5_K_M | 5 | 5.8 GB | High | B68 |
Q6_K | 6 | 6.6 GB | High | B69 |
Q8_0Best for your GPU | 8 | 8.6 GB | Very High | A71 |
F16 | 16 | 16.4 GB | Maximum | F0 |
| 27B | S | 17.3 tok/s |
| 30B | A | 43.3 tok/s |
| 9B | S | 94 tok/s |