Can Surface Laptop Ultra · RTX Spark N1X (20-core) · 128 GB run Qwen3.5 27B?
128 GB unified · 300 GB/s memory bandwidth · Qwen3.5 27B has 27.8B parameters.
Short answer
Yes, acceptable for chat and acceptable or better for every workload we test.
Best quantization for chat: Q6_K (22 GB of weights) on Ollama. Generation: 6–11 tok/s, leaving about 93 GB free for your other apps.
How it rates for each workload
Same model and machine, different jobs. Agents and long documents send far bigger prompts than chat, so they need much more speed and memory.
| Workload | Verdict | Quant | Generation | First reply | Context | |
|---|---|---|---|---|---|---|
| Chatwith Open WebUI | Acceptable | Q6_K | 6–11 tok/s | under 1 s | 8K | Details |
| Coding questionswith Continue | Acceptable | Q4_K_M | 9–14 tok/s | ≈3 s | 16K | Details |
| Coding in a repositorywith Aider | Acceptable | Q4_K_M | 8–14 tok/s | ≈8 s | 32K | Details |
| Agentic codingwith OpenCode | Acceptable | Q3_K_M | 10–16 tok/s | ≈15 s | 32K | Details |
| Long documents (64K)with Open WebUI | Acceptable | Q6_K | 6–9 tok/s | ≈35 s | 64K | Details |
Speeds are bandwidth-based estimates; no direct benchmark exists for this pair. “First reply” is the time to read the workload’s opening prompt. How we calculate
Get it running
Copy-paste commands for the Q6_K build with a 64K context. Ollama and llama.cpp download the file straight from Hugging Face.
ollama run hf.co/unsloth/Qwen3.5-27B-GGUF:Q6_K
Downloads 22.45 GB (Q6_K). Ollama's default context is small: set OLLAMA_CONTEXT_LENGTH=65536 before `ollama serve` for long prompts.
Other models for Surface Laptop Ultra · RTX Spark N1X (20-core) · 128 GB
The best-rated models for chat on this machine.
- gpt-oss-120b40–65 tok/sExcellent
- Qwen3.6 35B-A3B45–75 tok/sExcellent
- Qwen3-Next 80B-A3B Instruct45–75 tok/sExcellent
- Gemma 4 26B-A4B35–60 tok/sExcellent
- LFM2.5 24B-A2B85–150 tok/sExcellent
- Qwen3.5 35B-A3B45–75 tok/sExcellent
Cheapest machines for Qwen3.5 27B
Hardware rated comfortable or better for chat, lowest price first.
- Desktop PC · Intel Arc Pro B60 24GB · 32 GB RAM$1,500 · 10–17 tok/sComfortable
- Desktop PC · Radeon RX 7900 XT · 32 GB RAM$1,550 · 25–40 tok/sExcellent
- Ryzen AI Max+ 395 mini PC / Framework Desktop · 64 GB$1,600 · 12–16 tok/sComfortable
- Desktop PC · Intel Arc Pro B60 24GB · 64 GB RAM$1,628 · 10–17 tok/sComfortable
- Desktop PC · GeForce RTX 3090 · 32 GB RAM$1,700 · 25–35 tok/sExcellent
- Mac mini M4 Pro 48 GB$1,799 · 11–14 tok/sComfortable
Same chip, other memory: 24 GB
Different tool, context size or workload?
These pages use typical settings. The full check models your exact setup.