MODEL ARCHITECTURE SPEC โ€ข ALIBABA CLOUD27.2B Dense

Qwen 3.8 27B Instruct VRAM & inference speed

27.2B Total ParamsDense Architecture64 Layers โ€ข 8 KV Heads32K Default Ctx (Max 128K)Ollama: qwen3.8:27b

Accurate memory requirements, KV cache footprint, and tokens/sec generation benchmarks for running Qwen 3.8 27B Instruct across local GPUs, Apple Silicon Macs, and cloud instances.

โšก Fits in VRAM (Tight Headroom โ€” Use Q8/Q4 KV Cache)21.93 GB (91%)~40 t/s

Model & Target Hardware

interactive
Agentic Coding, Terminal Workflows & Multi-File Refactoring
Qwen 3.8 27B Instruct on NVIDIA GeForce RTX 4090 (24GB GDDR6X)

โšก Tight Fit โ€” Runs 100% on GPU (Low Headroom)

โšก TIGHT FIT
Required VRAM
21.93 GB
91% of hardware capacity (24 GB)
Est. Decode Speed
~40 tok/s
Dense model @ 1008 GB/s
Available Headroom
+2.07 GB
Safe for OS display & full context
Memory Allocation & Headroom
21.93 GB allocated of 24 GB capacity
91% utilized
Weights: 16.32 GB
KV: (32K): 4.29 GB
Overhead: 1.32 GB
Free Headroom: +2.07 GB
โšก Architecture & Throughput Transparency: Single-user decode speed (~40 tok/s) is memory-bandwidth bound at batch size = 1 on NVIDIA GeForce RTX 4090 (24GB GDDR6X) (1008 GB/s). Prompt prefill / TTFT (~580 tok/s) is compute-bound and utilizes GPU Tensor cores. Actual latency varies with FlashAttention-2 and runtime engine (Ollama/vLLM/llama.cpp).
OLLAMA_FLASH_ATTENTION=1 OLLAMA_KV_CACHE_TYPE=q8_0 ollama run qwen3.8:27b

Quantization Precision Matrix

32K ctx โ€ข KV: Q8_0
QuantizationWeightsKV CacheTotal VRAMEst. SpeedFit Status
FP1616 bpw54.4 GB4.29 GB61.34 GB (256%)0 t/sOOM
Q8_08.5 bpw28.83 GB4.29 GB34.88 GB (145%)0 t/sOOM
Q6_K6.56 bpw22.3 GB4.29 GB28.12 GB (117%)~6 t/sPARTIAL
Q5_K_M5.68 bpw19.31 GB4.29 GB25.03 GB (104%)~7 t/sPARTIAL
Q4_K_M4.8 bpw16.32 GB4.29 GB21.93 GB (91%)~40 t/sFITS
FP44.25 bpw14.42 GB4.29 GB19.96 GB (83%)~44 t/sFITS
IQ3_XS3.3 bpw11.15 GB4.29 GB16.58 GB (69%)~56 t/sFITS

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Hardware Compatibility Matrix for Qwen 3.8 27B Instruct

Standard Q4_K_M precision with 32K context window and Q8_0 KV cache

12 Systems Benchmarked
Hardware SystemVRAM EnvelopeRequired VRAMHeadroomEst. Decode SpeedCompatibilityTest Fit
NVIDIA GeForce RTX 5090 (32GB GDDR7)
Consumer GPU โ€ข 1792 GB/s
32 GB21.93 GB+10.07 GB~70 tok/sโœ“ FITSTest Fit โ†’
NVIDIA GeForce RTX 4090 (24GB GDDR6X)
Consumer GPU โ€ข 1008 GB/s
24 GB21.93 GB+2.07 GB~40 tok/sโšก TIGHT FITTest Fit โ†’
2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM)
Multi-GPU Rig โ€ข 936 GB/s
48 GB21.93 GB+26.07 GB~34 tok/sโœ“ FITSTest Fit โ†’
NVIDIA GeForce RTX 5080 (16GB GDDR7)
Consumer GPU โ€ข 960 GB/s
16 GB21.93 GB-5.93 GB0 (OOM)โœ• OOMTest Fit โ†’
NVIDIA RTX 4070 Ti Super (16GB)
Consumer GPU โ€ข 672 GB/s
16 GB21.93 GB-5.93 GB0 (OOM)โœ• OOMTest Fit โ†’
NVIDIA GeForce RTX 3060 (12GB)
Consumer GPU โ€ข 360 GB/s
12 GB21.93 GB-9.93 GB0 (OOM)โœ• OOMTest Fit โ†’
Apple Mac Mini M4 Pro (64GB Unified Memory)
Apple Silicon โ€ข 273 GB/s
54 GB21.93 GB+32.07 GB~10 tok/sโœ“ FITSTest Fit โ†’
Apple Mac Studio M4 Max (128GB Unified Memory)
Apple Silicon โ€ข 546 GB/s
112 GB21.93 GB+90.07 GB~20 tok/sโœ“ FITSTest Fit โ†’
Apple Mac Studio M5 Ultra (256GB Unified Memory)
Apple Silicon โ€ข 890 GB/s
236 GB21.93 GB+214.07 GB~33 tok/sโœ“ FITSTest Fit โ†’
AMD Strix Halo Mini-PC (Ryzen AI Max+ 395 128GB)
Unified APU / Mini-PC โ€ข 256 GB/s
110 GB21.93 GB+88.07 GB~8 tok/sโœ“ FITSTest Fit โ†’
NVIDIA DGX Spark (128GB Grace-Blackwell Unified)
AI Appliance โ€ข 273 GB/s
118 GB21.93 GB+96.07 GB~11 tok/sโœ“ FITSTest Fit โ†’
NVIDIA H100 SXM (80GB HBM3 Cloud GPU)
Datacenter Cloud GPU โ€ข 3350 GB/s
80 GB21.93 GB+58.07 GB~139 tok/sโœ“ FITSTest Fit โ†’