Single-node multi-GPUNVLinkintermediate

What runs on Dual RTX 3090 (24 GB × 2)?

The reference dual-GPU local-AI rig. NVLink optional. 48 GB total / ~46 GB effective with tensor parallelism. The cheapest path to 70B-class models at 2025-2026 prices.

At a glance
Effective VRAM
46 / 48 GB
Not pooled
Speed penalty
~10%
vs ideal single-card
Recommended runtime
vllm
tensor parallel
Setup difficulty
intermediate
~700W peak
24
Models fit
12
Borderline
8
Not practical
Deployment recipe
Dual RTX 3090 workstation →

Step-by-step setup with NVLink bridge verification, vLLM tensor-parallel-2 configuration, and operator-grade failure modes.

Memory budget
Total VRAM
48 GB
Effective for inference
46 GB
96% of total
Not pooled

PCIe + optional NVLink between two RTX 3090s does NOT pool VRAM the way Apple unified memory does. Each card holds its half of the model weights via tensor parallelism (vLLM / SGLang) or pipeline parallelism (llama.cpp layer split). Effective VRAM is roughly total minus ~2 GB per card for activations, KV cache, and runtime overhead. Concretely: a 70B Q4 model (~40 GB weights) fits with ~6 GB of headroom for context and KV. Anything claiming 48 GB pooled is wrong.

Why total VRAM is not the whole story

Two cards with NVLink bridge. NVLink (~112.5 GB/s bidirectional) keeps tensor-parallel efficient but does NOT pool memory. Each card holds its share via tensor or pipeline parallelism. Effective 46 GB of total 48 GB.

See the multi-GPU guide for topology tradeoffs, and the RunLocalAI Will-It-Run Framework for the citable fit-tier method.

Topology

Topology
single-node-multi-gpu
Interconnect
nvlink~112.5 GB/s
Component count
2 units
Components
Recommended runtime
vllm
Also: sglang, exllamav2, tgi
Recommended split strategy
tensor-parallel
Also: pipeline-parallel
Setup difficulty
intermediate
~700W peak

Models that fit comfortably (24)

Effective VRAM utilization ≤ 85% at the smallest production quant. Comfortable headroom for KV cache.

Jamba 1.5 Mini
Fits
52B·Q4_K_M → 36 GB·78% of effective VRAM·~10% speed penalty vs ideal
Nemotron 3 Super 49B
Fits
49B·AWQ-INT4 → 32 GB·70% of effective VRAM·~10% speed penalty vs ideal
Mixtral 8x7B Instruct
Fits
47B·Q4_K_M → 32 GB·70% of effective VRAM·~10% speed penalty vs ideal
Mixtral 8X7B Instruct v0.1 GPTQ
Fits
46.7B·Q4_K_M → 33 GB·72% of effective VRAM·~10% speed penalty vs ideal
ALIA 40b instruct 2601
Fits
40B·Q4_K_M → 28 GB·61% of effective VRAM·~10% speed penalty vs ideal
Falcon 40B Instruct
Fits
40B·Q4_K_M → 28 GB·61% of effective VRAM·~10% speed penalty vs ideal
Command R 35B
Fits
35B·Q4_K_M → 26 GB·57% of effective VRAM·~10% speed penalty vs ideal
Qwen3.5 35B-A3B
Fits
35B·Q4_K_M → 28 GB·61% of effective VRAM·~10% speed penalty vs ideal
Qwen3.6 35B-A3B
Fits
35B·Q4_K_M → 28 GB·61% of effective VRAM·~10% speed penalty vs ideal
Aya 23 35B
Fits
35B·Q4_K_M → 24 GB·52% of effective VRAM·~10% speed penalty vs ideal
Mihenk LLM v2 35B (Turkish Financial)
Fits
35B·Q4_K_M → 25 GB·54% of effective VRAM·~10% speed penalty vs ideal
Ornith 1.0 35B
Fits
35B·Q4_K_M → 25 GB·54% of effective VRAM·~10% speed penalty vs ideal
Phind CodeLlama 34B v2
Fits
34B·Q4_K_M → 24 GB·52% of effective VRAM·~10% speed penalty vs ideal
Yi 1.5 34B
Fits
34B·Q4_K_M → 24 GB·52% of effective VRAM·~10% speed penalty vs ideal
DeepSeek Coder V3
Fits
33B·AWQ-INT4 → 22 GB·48% of effective VRAM·~10% speed penalty vs ideal
Nemotron 3 Nano Omni 33B
Fits
33B·Q4_K_M → 32 GB·70% of effective VRAM·~10% speed penalty vs ideal
Laguna XS 2.1
Fits
33B·Q4_K_M → 24 GB·52% of effective VRAM·~10% speed penalty vs ideal
DeepSeek R1 Distill Qwen 32B
Fits
32B·Q4_K_M → 24 GB·52% of effective VRAM·~10% speed penalty vs ideal
EXAONE 3.5 32B Instruct
Fits
32B·Q4_K_M → 23 GB·50% of effective VRAM·~10% speed penalty vs ideal
EXAONE 3.5 32B Instruct AWQ
Fits
32B·Q4_K_M → 23 GB·50% of effective VRAM·~10% speed penalty vs ideal
Magistral 32B
Fits
32B·AWQ-INT4 → 22 GB·48% of effective VRAM·~10% speed penalty vs ideal
DeepSeek R1 Distill Qwen 3 32B
Fits
32B·AWQ-INT4 → 22 GB·48% of effective VRAM·~10% speed penalty vs ideal
EXAONE 4.0.1 32B
Fits
32B·Q4_K_M → 23 GB·50% of effective VRAM·~10% speed penalty vs ideal
Pollux Judge 32B
Fits
32B·Q4_K_M → 23 GB·50% of effective VRAM·~10% speed penalty vs ideal

Borderline (12)

Fits but with little headroom. KV cache for long context may not fit; verify before deployment.

InternVL 2.5 78B
Borderline
78B·Q4_K_M → 52 GB·113% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >113% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Qwen 2.5 Math 72B
Borderline
72B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Qwen 2.5 72B Instruct
Borderline
72B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Molmo 72B
Borderline
72B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Qwen 2.5-VL 72B
Borderline
72B·AWQ-INT4 → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Tulu 3 70B
Borderline
70B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Dolphin 3 Llama 3.3 70B
Borderline
70B·AWQ-INT4 → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Llama 3.3 70B Instruct
Borderline
70B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Llama 3.1 70B Instruct
Borderline
70B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

DeepSeek R1 Distill Llama 70B
Borderline
70B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

EVA Llama 3.3 70B
Borderline
70B·AWQ-INT4 → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

OpenBioLLM Llama 3 70B
Borderline
70B·Q4_K_M → 48 GB·104% of effective VRAM·~10% speed penalty vs ideal

Effective VRAM utilization >104% — KV cache for long context will not fit. Cap context at ~4-8K or move to a larger combo.

Not practical (8)

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly. Drop to a smaller quant or move to a larger combo.

DeepSeek V4 Pro (1.6T MoE)
Not practical
1600B·Q4_K_M → 1024 GB·2226% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

Step-3
Not practical
1000B·AWQ-INT4 → 640 GB·1391% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

Kimi K2.6
Not practical
1000B·Q4_K_M → 700 GB·1522% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

DeepSeek V4
Not practical
745B·AWQ-INT4 → 480 GB·1043% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

Mistral Medium 3.5 (675B MoE)
Not practical
675B·Q4_K_M → 448 GB·974% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

DeepSeek V3 (671B MoE)
Not practical
671B·Q4_K_M → 420 GB·913% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

DeepSeek R1 (671B reasoning)
Not practical
671B·Q4_K_M → 420 GB·913% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

Llama 4 405B
Not practical
405B·AWQ-INT4 → 280 GB·609% of effective VRAM·~10% speed penalty vs ideal

Model weights exceed effective combo VRAM. Even with the recommended split strategy, this configuration won't run cleanly.

Benchmark opportunities

estimates, not measurements

Pending benchmark targets for this combo. Once measured, results land in the catalog as benchmarks.

Dual RTX 3090 + Llama 3.3 70B Q4 (vLLM tensor-parallel)
pending
Estimate: 25-32 tok/s decode (NVLink)

Reference benchmark for the dual-3090 NVLink prosumer build. vLLM tensor-parallel-2, AWQ-INT4, 8K context. Compare against dual-4090 PCIe (no NVLink) to isolate interconnect impact.

Going deeper