Can an RTX 4070 run Qwen3-8B?
Yes, with room to spare Qwen3-8B at Q4_K_M needs 5.93 GiB–6.48 GiB at 8,192 tokens of context. The RTX 4070 has about 11 GiB usable.
File: Qwen3-8B-Q4_K_M.gguf (5.0 GB).
These are estimates from the model's config and file sizes, not measurements. How we calculate
How much room is left
- Context can grow to about 30,720 tokens before it stops fitting cleanly.
- A larger file also fits: GGUF Q6_K (Qwen) needs about 8.1 GiB (Fits).
Other files on this GPU
| Quant | File size | Engine | Total | Fit |
|---|---|---|---|---|
| BF16 safetensors | 16.4 GB | vllm | 17.0 GiB–18.9 GiB | Does not fit |
| GGUF Q8_0 | 8.7 GB | llama.cpp | 9.4 GiB–10.0 GiB | Tight fit |
| GGUF Q6_K (Qwen) | 6.7 GB | llama.cpp | 7.5 GiB–8.1 GiB | Fits |
| GGUF Q5_K_M (Qwen) | 5.9 GB | llama.cpp | 6.7 GiB–7.3 GiB | Runs comfortably |
| GGUF Q4_K_M This page | 5.0 GB | llama.cpp | 5.9 GiB–6.5 GiB | Runs comfortably |
Same context (8,192 tokens), one chat at a time, each file with its usual engine.
Settings used
- ModelQwen3-8B
- HardwareGeForce RTX 4070 12GB (desktop, GDDR6X)
- QuantizationGGUF Q4_K_M
- Context length (cached tokens)8,192
- Engine
llama.cpp - Concurrent sequences1
- KV cache typefp16
Technical identifiers and share data
- Model
qwen3-8b - Hardware
nvidia-geforce-rtx-4070-12gb-desktop - Quantization
gguf-q4_k_m - Share fragment for this identity
v2.eyJzY2hlbWFWZXJzaW9uIjoyLCJjYWxjdWxhdG9yVmVyc2lvbiI6IjAuMy4wIiwiZGF0YXNldFZlcnNpb24iOiIyMDI2LTEwLTAyLjEiLCJjb25maWciOnsibW9kZWxJZCI6InF3ZW4zLThiIiwiaGFyZHdhcmVJZCI6Im52aWRpYS1nZWZvcmNlLXJ0eC00MDcwLTEyZ2ItZGVza3RvcCIsImRldmljZUNvdW50IjoxLCJxdWFudGl6YXRpb25JZCI6ImdndWYtcTRfa19tIiwiY29udGV4dFRva2VucyI6ODE5MiwiY29uY3VycmVudFNlcXVlbmNlcyI6MSwiZW5naW5lIjoibGxhbWEuY3BwIiwia3ZUeXBlIjoiZnAxNiJ9fQ
How this number is calculated
Total = weight file + KV cache + runtime buffers. The range spans low to high runtime overhead for the engine shown.
- Weights (file)
- 4.68 GiB (5,027,783,488 bytes)
- KV cache
- 1.13 GiB (1,207,959,552 bytes)
- Runtime buffers
- 0.13 GiB–0.67 GiB
- Total
- 5.93 GiB–6.48 GiB
- Usable memory
- 11.00 GiB
- OS / display reserve
- 1.00 GiB
- Left over
- 4.52 GiB–5.07 GiB
6.48 GiB high estimate vs 11.00 GiB net
Enough memory does not mean this engine, quant, and OS will run. Support does not mean it will be fast.
- Requested context is within the recorded native window of 40960 tokens.
- Full-resident weight estimates use total parameters, including inactive MoE experts.
- Weight bytes come from the selected weight files only, not from every file in the repository.
- Download file size is not peak GPU memory. Runtime layout, allocator padding, and KV are extra.
- Counted files: Qwen3-8B-Q4_K_M.gguf.
- Context budget is the number of cached tokens per sequence (prompt plus reserved generation).
- Concurrent sequences share one model replica; weights are not multiplied by sequence count.
- KV dtype is independent of weight quantization unless you change it.
Related pages
Sources
- Qwen3-8B model card
- config.json — revision b968826d9c46dd6066d109eabc6255188de91218
- safetensors index — metadata.total_size=16381470720
- Artifact repo Qwen/Qwen3-8B-GGUF
- NVIDIA GeForce RTX 40 Series specs — Original 12 GB GDDR6X SKU, not the later GDDR6 variant
Calculator
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