OpenChat 7B needs ~9.4 GB VRAM. RTX 4000 Ada 20GB has 20.0 GB. With Q4_K_M quantization, expect ~71 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
70.7 tok/s
TTFT
2739 ms
Safe context
8K
Memory
9.4 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 | C | Runs well | 70.7 tok/s | 1494 ms | 8K |
| Coding | C | Runs well | 70.7 tok/s | 2739 ms | 8K |
| Agentic Coding | B | Runs well | 70.7 tok/s | 3983 ms | 8K |
| Reasoning | C | Runs well | 70.7 tok/s | 3237 ms | 8K |
| RAG | B | Runs well | 70.7 tok/s | 4979 ms | 8K |
Inference speed
Estimated decode speed (tokens/sec) for OpenChat 7B at Q4_K_M across popular GPUs and Apple Silicon, using the fastest local runtime per device. Fastest is RTX 5090 32GB at ~98 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? |
|---|---|---|---|---|
 RTX 5090 32GB | 32 GB | Q4_K_M | 98.0 | Fits |
| RTX 4090 24GB | 24 GB | Q4_K_M | 98.0 | Fits |
| RTX 4080 Super 16GB | 16 GB | Q4_K_M | 98.0 | Fits |
| RTX 3090 24GB | 24 GB | Q4_K_M | 98.0 | Fits |
RX 7900 XTX 24GB | 24 GB | Q4_K_M | 98.0 | Fits |
Mac Studio M3 Ultra 256GB | 256 GB | Q4_K_M | 98.0 | Fits |
Mac Studio M2 Ultra 128GB | 128 GB | Q4_K_M | 98.0 | Fits |
Mac Studio M1 Ultra 128GB | 128 GB | Q4_K_M | 98.0 | Fits |
| RTX 4070 12GB | 12 GB | Q4_K_M | 95.2 | Fits |
MacBook Pro M4 Max 128GB | 128 GB | Q4_K_M | 94.4 | Fits |
MacBook Pro M4 Max 64GB | 64 GB | Q4_K_M | 94.4 | Fits |
MacBook Pro M3 Max 64GB | 64 GB | Q4_K_M | 60.4 | Fits |
| RTX 3060 12GB | 12 GB | Q4_K_M | 59.8 | Fits |
MacBook Pro M1 Max 64GB | 64 GB | Q4_K_M | 55.4 | Fits |
MacBook Pro M4 Pro 48GB | 48 GB | Q4_K_M | 48.7 | Fits |
| RTX 4060 8GB | 8 GB | Q4_K_M | 46.0 | Offloads |
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 OpenChat 7B (7B params) fits at each quantization level on RTX 4000 Ada 20GB (20.0 GB usable).
| Quant | Bits | VRAM | Quality | Fit |
|---|---|---|---|---|
Q2_K | 2 | 2.7 GB | Low | C47 |
Q3_K_S | 3 | 3.4 GB | Low | C48 |
NVFP4 | 4 | 3.9 GB | Medium | C48 |
Q4_K_M | 4 | 4.3 GB | Medium | C48 |
Q5_K_M | 5 | 5.0 GB | High | C49 |
Q6_K | 6 | 5.7 GB | High | C49 |
Q8_0 | 8 | 7.5 GB | Very High | C51 |
F16Best for your GPU | 16 | 14.3 GB | Maximum | C52 |
Copy-paste commands to run OpenChat 7B on your machine.
Run
ollama run openchatYes, RTX 4000 Ada 20GB can run OpenChat 7B with a C grade (Runs well). Expected decode speed: 70.7 tok/s.
OpenChat 7B (7B parameters) requires approximately 9.4 GB of memory with Q4_K_M quantization.
The recommended quantization for OpenChat 7B is Q4_K_M, which balances quality and memory efficiency.
On RTX 4000 Ada 20GB, OpenChat 7B achieves approximately 70.7 tokens per second decode speed with a time-to-first-token of 2739ms using Q4_K_M quantization.
For coding workloads, OpenChat 7B on RTX 4000 Ada 20GB receives a C grade with 70.7 tok/s and 8K context.
On RTX 4000 Ada 20GB, OpenChat 7B 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/openchat-7b-on-rtx-4000-ada-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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