Model × hardware check
Can gpt-oss-20b run on NVIDIA GeForce RTX 4060 Ti · 16 GB?
It fits only with limited headroom at 8,192 tokens. a compact MoE package for local coding and agent experiments The RTX 4060 Ti 16GB has more capacity than the 3060 but a narrower 288 GB/s memory path, making it a useful capacity-versus-speed comparison.
Short answer
Tight fit
The estimate fits, but with less than 20% headroom. Close other applications, reduce context, or choose a smaller quantization.
- Available VRAM
- 16 GB
- Estimated requirement
- 13.8 GB
- Headroom
- +2.2 GB
- Fit ratio
- 116%
- Recommended quantization
- MXFP4
- Context ceiling
- 95,740 tokens
- Speed estimate
- Estimate · Fast relative band
What the numbers say
The selected gpt-oss-20b package uses 12.1 GB of weight files. The 8K KV cache estimate is 0.2 GB, and the formula adds 1.5 GB of runtime overhead. That produces a 13.8 GB requirement against 16 GB of VRAM.
The 16 GB version gives compact models more room, but its narrower memory bus can be a speed constraint compared with higher-bandwidth cards.
The context ceiling shown above is the point where the same formula reaches the machine's capacity. It is not a promise that the backend can allocate that full context after the operating system and other applications take their share.
Quantization trade-offs at 8K
| Quantization | Weight files | 8K requirement | Fit on this machine | Context ceiling | Speed estimate | Ollama |
|---|---|---|---|---|---|---|
| MXFP4 | 12.11 GB | 13.8 GB | Tight fit · 116% | 95,740 tokens | Estimate · Fast relative class | ollama run gpt-oss:20b |
For MoE models, a tight CPU-offload result means the weights fit in system memory even when they do not fit in accelerator memory. That does not increase the accelerator context ceiling.
Run commands
ollama run gpt-oss:20blms get "gpt-oss-20b"@mxfp4
lms load <model-key-from-lms-ls> --gpu max --context-length 8192llama-cli -hf openai/gpt-oss-20b -c 8192 -ngl 99 -p "Your prompt"Commands are examples, not a guarantee that the selected quantization tag is available in every runtime. Confirm the package name and license on the linked model page.
If it does not fit
Needs about 0.6 GB more VRAM for comfort
The calculator targets 20% headroom, so the practical upgrade target is approximately 16.6 GB of VRAM, not just the bare 13.8 GB minimum.
Low-cost setup upgrades
Useful upgrades around NVIDIA GeForce RTX 4060 Ti · 16 GB
These are optional setup improvements, not a claim that an accessory can increase GPU or unified-memory capacity.
External NVMe SSD for model storage
Keeps large GGUF and MLX files off the boot drive. Fast storage reduces load time, but it does not increase the memory available for inference.
Search current listings on AmazonDesktop RAM upgrade kit
Useful for MoE CPU offload and keeping the operating system out of VRAM. Match the motherboard's memory type, slot layout, capacity limit, and validated part numbers.
Search current listings on AmazonGPU support bracket
A lower-cost mechanical upgrade for heavy three-slot cards. Check clearance, mounting height, and whether the bracket blocks fans or case panels.
Search current listings on AmazonAs an Amazon Associate, LocalLM Fit earns from qualifying purchases. Links are sponsored search links and do not change the price you pay. Affiliate disclosure.
Where this estimate can break
- The Harmony response format is required; using an unrelated chat format can produce incorrect output.
- OpenAI's 16 GB guidance is for the MXFP4 build and does not guarantee room for a long context.
- Other GPU applications, display buffers, and the operating system reduce usable memory.
- Longer prompts, concurrent requests, and a different backend can raise peak memory.
Compare this pairing
FAQ
Questions about this pairing.
How much memory does gpt-oss-20b need on NVIDIA GeForce RTX 4060 Ti · 16 GB?
At an 8K context with MXFP4, the estimate is 13.8 GB: 12.1 GB of weights, 0.2 GB of KV cache, and 1.5 GB of runtime overhead. The available VRAM is 16 GB.
What context length can NVIDIA GeForce RTX 4060 Ti · 16 GB handle with this model?
The calculated ceiling is 95,740 tokens for this quantization, capped by the model's native 131,072-token context. Actual usable context can be lower after the OS, other applications, and backend workspace.
How does quantization change the memory requirement on NVIDIA GeForce RTX 4060 Ti · 16 GB?
At 8,192 tokens, the published variants calculate as follows: MXFP4: 13.8 GB, tight fit. A lower-bit file can move a result from too large to tight, but quality and kernel support may differ.
What can I run if gpt-oss-20b does not fit on NVIDIA GeForce RTX 4060 Ti · 16 GB?
Reaching the 20% comfort threshold would need about 0.6 GB more VRAM. Models that fit this machine in the current catalog include Gemma 4 12B Unified, Qwen3 8B, Gemma 4 E4B.
Is the speed estimate for gpt-oss-20b on NVIDIA GeForce RTX 4060 Ti · 16 GB measured?
No. Fast relative band is a heuristic band derived from 3.6B active parameters and 288 GB/s published memory bandwidth. Backend kernels, batch size, thermals, and CPU offload can change actual tokens per second.