HARDWARE FIT CHECK โ€ข Qwen 3.8 27B Instruct + 2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM)21.93 GB / 48 GB VRAM

Can I Run Qwen 3.8 27B Instruct on 2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM)?

Full VRAM footprint analysis, tokens/sec generation benchmark, and copy-paste Ollama & vLLM runtime commands for running Qwen 3.8 27B Instruct (27.2B) on 2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM) (48 GB).

โœ… Runs 100% in GPU VRAM (Optimal Headroom)21.93 GB (46%)~34 t/s

Model & Target Hardware

interactive
Agentic Coding, Terminal Workflows & Multi-File Refactoring
Qwen 3.8 27B Instruct on 2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM)

โœ“ Fits Comfortably in VRAM

โœ“ FITS IN VRAM
Required VRAM
21.93 GB
46% of hardware capacity (48 GB)
Est. Decode Speed
~34 tok/s
Dense model @ 936 GB/s
Available Headroom
+26.07 GB
Safe for OS display & full context
Memory Allocation & Headroom
21.93 GB allocated of 48 GB capacity
46% utilized
Weights: 16.32 GB
KV: (32K): 4.29 GB
Overhead: 1.32 GB
Free Headroom: +26.07 GB
โšก Architecture & Throughput Transparency: Single-user decode speed (~34 tok/s) is memory-bandwidth bound at batch size = 1 on 2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM) (936 GB/s). Prompt prefill / TTFT (~493 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 (128%)~2 t/sPARTIAL
Q8_08.5 bpw28.83 GB4.29 GB34.88 GB (73%)~19 t/sFITS
Q6_K6.56 bpw22.3 GB4.29 GB28.12 GB (59%)~25 t/sFITS
Q5_K_M5.68 bpw19.31 GB4.29 GB25.03 GB (52%)~29 t/sFITS
Q4_K_M4.8 bpw16.32 GB4.29 GB21.93 GB (46%)~34 t/sFITS
FP44.25 bpw14.42 GB4.29 GB19.96 GB (42%)~38 t/sFITS
IQ3_XS3.3 bpw11.15 GB4.29 GB16.58 GB (35%)~48 t/sFITS

Local Hardware Configurations & Pricing

High-bandwidth VRAM specs and current market prices
Multi-GPU Rig48 GB VRAM

2x NVIDIA RTX 3090 Dual Rig (48GB Total VRAM)

Best price-to-VRAM homelab rig for 70B Q4_K_M & Qwen 3.8 27B Q8

936 GB/s700W TDP
Consumer GPU32 GB VRAM

NVIDIA GeForce RTX 5090 (32GB GDDR7)

Maximum tokens/sec on 27Bโ€“35B models & Blackwell FP4 quantization

1792 GB/s575W TDP
Consumer GPU24 GB VRAM

NVIDIA GeForce RTX 4090 (24GB GDDR6X)

The 24GB CUDA enthusiast standard for 14Bโ€“32B Q4_K_M models

1008 GB/s450W TDP
Consumer GPU16 GB VRAM

NVIDIA GeForce RTX 5080 (16GB GDDR7)

Blazing fast 8Bโ€“14B coding models with FP4/Q6_K precision

960 GB/s360W TDP

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