Recommendations · October 2026
The best local LLMs for the RTX 4000 Ada
Every model worth running on 20GB of GDDR6 ECC, which quantization to pick, and how fast each one generates text.
Our picks at a glance
- Best overall (also coding, reasoning, vision): Qwen3.8 27B (Q4_K_M, ~17 tokens/sec)
- Runner-up: Gemma 4 26B A4B (Q4_K_M, ~63 tokens/sec)
- Fastest good model (also largest that fits): Qwen3.6 35B-A3B (Q3_K_M, ~88 tokens/sec)
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01 · Best overall · also coding, reasoning, vision
Qwen3.8 27B
Qwen3.8 27B (27B) fits, with little room to spare in the RTX 4000 Ada's memory at Q4_K_M, using about 18GB with 8K context and generating ~17 tokens/sec. It is the most capable model in our catalog that runs well on this card. It is also our top pick for coding, reasoning and working with images.
Qwen3.8 27B, released in August 2026, is one of the strongest open models that fits a single 24GB GPU, with image input, a 262K native context, and switchable thinking. It uses the same hybrid layout as the Qwen3.5 and 3.6 27B models, where three of every four layers use linear attention, so long contexts cost far less memory than on older dense models. At Q4_K_M it needs about 18GB with 8K context, leaving room for 64K or more of context on a 24GB card, and 32GB cards can run Q6_K. It supersedes Qwen3.6 27B and Qwen3 32B, but its long reasoning traces make speed on slower hardware a real consideration.
- Quantization
- Q4_K_M
- Memory used
- 18.1 GB
- Speed (est.)
- ~17 tok/s
- Max context
- ~21K
$ ollama run qwen3.8:27bModel details →02 · Runner-up
Gemma 4 26B A4B
Gemma 4 26B A4B (26B (3.8B active)) fits comfortably in the RTX 4000 Ada's memory at Q4_K_M, using about 17GB with 8K context and generating ~63 tokens/sec. It is the next-best model that runs well here, and the one to try if the top pick doesn't suit you.
Gemma 4 26B A4B is Google's mixture-of-experts Gemma, with 26B total parameters and 3.8B active (128 experts, 8 used per token), image input, a 256K context, and a thinking mode. Because so few parameters are active, it generates text at small-model speed while matching much larger dense models on reasoning benchmarks. At Q4_K_M it needs about 17GB with 8K context, so it fits a 24GB GPU with plenty of room for context; on 16GB cards it runs at Q3_K_M or with a few experts in system RAM. It replaces Gemma 3 27B for most local uses.
- Quantization
- Q4_K_M
- Memory used
- 17.3 GB
- Speed (est.)
- ~63 tok/s
- Max context
- ~88K
$ ollama run gemma4:26bModel details →03 · Fastest good model · also largest that fits
Qwen3.6 35B-A3B
Qwen3.6 35B-A3B (35B (3B active)) fits, with little room to spare in the RTX 4000 Ada's memory at Q3_K_M, using about 19GB with 8K context and generating ~88 tokens/sec. Pick it when responsiveness matters more than squeezing out maximum quality. It is also the largest model that runs fully on this GPU.
Qwen3.6 35B-A3B is the April 2026 refresh of Qwen's fast mixture-of-experts model, focused on agentic coding and on preserving its reasoning across multi-turn tool use. With only 3B active parameters it generates text very quickly, and its hybrid linear attention keeps the KV cache tiny: the full 262K context needs about 5GB. At Q4_K_M it needs about 24GB with 8K context, which is tight on a 24GB card and comfortable on 32GB GPUs and Macs with 36GB or more; 12GB to 16GB GPUs run it well with experts offloaded to system RAM. It replaces Qwen3 30B-A3B and Qwen3 Coder 30B-A3B for most local users.
- Quantization
- Q3_K_M
- Memory used
- 19.2 GB
- Speed (est.)
- ~88 tok/s
- Max context
- ~0
$ ollama run qwen3.6:35bModel details →The full list
Every model that runs on the RTX 4000 Ada
| # | Model | Best quant | Memory | Speed | Fit |
|---|---|---|---|---|---|
| 1 | Qwen3.8 27B27B | Q4_K_M | 18.1 GB | ~17 tok/s | Fits, tight |
| 2 | Gemma 4 26B A4B26B (3.8B active) | Q4_K_M | 17.3 GB | ~63 tok/s | Runs well |
| 3 | Qwen3.6 35B-A3B35B (3B active) | Q3_K_M | 19.2 GB | ~88 tok/s | Fits, tight |
| 4 | Gemma 4 31B31B | Q3_K_M | 18.5 GB | ~18 tok/s | Fits, tight |
| 5 | gpt-oss-20b20.9B (3.6B active) | MXFP4 | 15.0 GB | ~62 tok/s | Runs well |
| 6 | Qwen3.5 9B9B | Q8_0 | 12.0 GB | ~26 tok/s | Runs well |
| 7 | Gemma 4 E4B8B | Q8_0 | 10.5 GB | ~30 tok/s | Runs well |
| 8 | Phi-414.7B | Q6_K | 15.0 GB | ~23 tok/s | Runs well |
Ranked by our capability score, adjusted for quantization and speed. Memory includes 8K context. Speeds are estimates for a single user; seemethodology.
Limits
Popular models that don't run well on 20GB
- gpt-oss-120bWon't fit
Needs about 68GB at MXFP4 with 8K context. It does not fit, even with CPU offload. See what hardware it needs.
- DeepSeek V4 FlashWon't fit
Needs about 168GB at FP4 with 8K context. It does not fit, even with CPU offload. See what hardware it needs.
- GLM-5.3-FlashWon't fit
Needs about 201GB at Q4_K_M with 8K context. It does not fit, even with CPU offload. See what hardware it needs.
- Qwen3.5 122B-A10BWon't fit
Needs about 77GB at Q4_K_M with 8K context. It does not fit, even with CPU offload. See what hardware it needs.
Setup
Best settings and software for the RTX 4000 Ada
NVIDIA cards have the broadest software support: everything runs on CUDA, usually on day one. With Qwen3.8 27B at Q4_K_M, you can fit roughly 21K tokens of context with a 16-bit KV cache; an 8-bit KV cache about doubles that.
- Ollama or LM Studio: the easiest way to download and chat with models.
- llama.cpp: full control over quantization, context, and offloading.
- vLLM or SGLang: best throughput when serving several users or agents at once.
- ExLlamaV3 / TabbyAPI: fast single-user inference with EXL3 quants that fill VRAM precisely.
New to quantization? Q4_K_M is the safe default; read our quantization explainer to see when Q5, Q6, or Q8 is worth the extra memory.
Upgrade path
Need more memory?
Memory capacity decides which models you can run. These are the most popular options with more memory than the RTX 4000 Ada.
Frequently asked questions
What is the best LLM for the RTX 4000 Ada?
Qwen3.8 27B is the best all-round model for the RTX 4000 Ada. At Q4_K_M it uses about 18GB with 8K context and generates ~17 tokens/sec.
What quantization should I use on the RTX 4000 Ada?
Use the highest-precision quant that leaves room for your context. Q4_K_M is the best default: it is about a quarter the size of the original 16-bit weights with only a small quality loss. If a model fits at Q5_K_M, Q6_K, or Q8_0 with room to spare, use that instead. Avoid going below Q3 except for very large models.
How much context can I use with Qwen3.8 27B on the RTX 4000 Ada?
At Q4_K_M with a 16-bit KV cache, roughly 21K tokens fit in 20GB. Quantizing the KV cache to 8-bit (for example with llama.cpp's --cache-type-k q8_0 --cache-type-v q8_0) roughly doubles that.
Can the RTX 4000 Ada run gpt-oss-120b?
No. gpt-oss-120b needs about 68GB at MXFP4 with 8K context, which is far more than 20GB plus 64GB of system RAM.
Can the RTX 4000 Ada run DeepSeek V4 Flash?
No. DeepSeek V4 Flash needs about 168GB at FP4 with 8K context, which is far more than 20GB plus 64GB of system RAM.