Granite Code 20B needs ~18.3 GB VRAM. RX 7900 XT 20GB has 20.0 GB. With Q4_K_M quantization, expect ~43 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
Tight fit
Decode
42.5 tok/s
TTFT
4556 ms
Safe context
8K
Memory
18.3 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 | Tight fit | 42.5 tok/s | 2485 ms | 8K |
| Coding | A | Tight fit | 42.5 tok/s | 4556 ms | 8K |
| Agentic Coding | B | Runs with offload (needs ~0.8 GB host RAM) | 27.5 tok/s | 10237 ms | 8K |
| Reasoning | A | Tight fit | 42.5 tok/s | 5385 ms | 8K |
| RAG | B | Runs with offload (needs ~0.8 GB host RAM) | 27.5 tok/s | 12796 ms | 8K |
Inference speed
Estimated decode speed (tokens/sec) for Granite Code 20B at Q4_K_M across popular GPUs and Apple Silicon, using the fastest local runtime per device. Fastest is RTX 5090 32GB at ~106 tok/s. Speed is memory-bandwidth bound, so cards that fit the whole model in VRAM run far faster than ones that offload to system RAM.
| GPU / Mac | Memory | Quant | Speed (tok/s) | Fits? |
|---|---|---|---|---|
| 32 GB | Q4_K_M | 106.3 | Fits | |
| 24 GB | Q4_K_M | 67.8 | Fits | |
RX 7900 XTX 24GB | 24 GB | Q4_K_M | 61.2 | Fits |
| 24 GB | Q4_K_M | 58.0 | Fits | |
Mac Studio M3 Ultra 256GB | 256 GB | Q4_K_M | 49.3 | Fits |
Mac Studio M2 Ultra 128GB | 128 GB | Q4_K_M | 41.1 | Fits |
Mac Studio M1 Ultra 128GB | 128 GB | Q4_K_M | 39.0 | Fits |
MacBook Pro M4 Max 128GB | 128 GB | Q4_K_M | 38.4 | Fits |
MacBook Pro M4 Max 64GB | 64 GB | Q4_K_M | 38.4 | Fits |
| 16 GB | Q4_K_M | 31.0 | Heavy offload | |
MacBook Pro M4 Pro 48GB | 48 GB | Q4_K_M | 24.2 | Fits |
MacBook Pro M3 Max 64GB | 64 GB | Q4_K_M | 21.2 | Fits |
MacBook Pro M1 Max 64GB | 64 GB | Q4_K_M | 19.5 | Fits |
| 12 GB | Q4_K_M | 11.0 | Too big | |
| 12 GB | Q4_K_M | 6.9 | Too big | |
| 8 GB | Q4_K_M | 2.6 | Too big |
Estimates for single-stream decoding at Q4_K_M; real tokens/sec varies with prompt length, context, batch size, and runtime build. Prompt processing (prefill) is faster than the decode figures shown here.
How Granite Code 20B (20B params) fits at each quantization level on RX 7900 XT 20GB (20.0 GB usable).
| Quant | Bits | VRAM | Quality | Fit |
|---|---|---|---|---|
Q2_K | 2 | 7.8 GB | Low | A79 |
Q3_K_S | 3 | 9.8 GB | Low | A81 |
NVFP4 | 4 | 11.2 GB | Medium | A80 |
Q4_K_M | 4 | 12.2 GB | Medium | A80 |
Q5_K_MBest for your GPU | 5 | 14.4 GB | High | A80 |
Q6_K | 6 | 16.4 GB | High | F0 |
Q8_0 | 8 | 21.4 GB | Very High | F0 |
F16 | 16 | 41.0 GB | Maximum | F0 |
Copy-paste commands to run Granite Code 20B on your machine.
Run
ollama run granite-code:20bYour hardware
| Model | Params | Grade | Decode | Capabilities |
|---|---|---|---|---|
| 30.5B | A | 40.7 tok/s | ||
| 27B | A | 18.3 tok/s | ||
| 27B | S | 17.3 tok/s | ||
| 30B | A | 43.3 tok/s | ||
| 24B | S | 35.2 tok/s |
Yes, RX 7900 XT 20GB can run Granite Code 20B with a A grade (Tight fit). Expected decode speed: 42.5 tok/s.
Granite Code 20B (20B parameters) requires approximately 18.3 GB of memory with Q4_K_M quantization.
The recommended quantization for Granite Code 20B is Q4_K_M, which balances quality and memory efficiency.
On RX 7900 XT 20GB, Granite Code 20B achieves approximately 42.5 tokens per second decode speed with a time-to-first-token of 4556ms using Q4_K_M quantization.
For coding workloads, Granite Code 20B on RX 7900 XT 20GB receives a A grade with 42.5 tok/s and 8K context.
On RX 7900 XT 20GB, Granite Code 20B can safely use up to 8K tokens of context. The model's official context limit is 8K, 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/granite-code-20b-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>
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