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Best Local LLMs for 8GB VRAM Consumer GPUs: Hardware Benchmarks

Hardware benchmark guide evaluating the best open-weight local LLMs for 8GB VRAM consumer GPUs. Includes token-per-second decoding speeds, context spillover, and quantization metrics.

Nadhebe Editorial Team Nadhebe Editorial Team
· · 4 min read
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Best Local LLMs for 8GB VRAM Consumer GPUs: Hardware Benchmarks

Consumer graphics cards featuring 8 GB of VRAM—such as the NVIDIA GeForce RTX 4060, RTX 3070, RTX 3060 Ti, and Apple M-series Macs with 16GB Unified Memory—represent the most widely deployed local hardware setup among software developers, AI engineers, and researchers.

However, local LLM execution on 8GB GPUs presents strict memory limits. If model weights, CUDA activation buffers, and KV cache memory exceed 8,192 MB of VRAM, the inference runtime spills memory onto System RAM over PCIe lanes, causing token decoding speeds to drop by up to 90%.

In this empirical benchmark guide, we test and rank the top open-weights language models optimized for 8GB VRAM consumer GPUs across throughput, memory footprint, coding benchmark accuracy, and context spillover thresholds.


8GB VRAM Hardware Architecture & PCIe Bottlenecks

Local model generation performance depends directly on Memory Bandwidth ($\text{BW}{\text{VRAM}}$). To compute theoretical max token decoding speed ($T{\text{max}}$) for dense models:

$$T_{\text{max}} = \frac{\text{BW}{\text{VRAM}} , (\text{GB/s})}{M{\text{Model_Weights}} , (\text{GB})}$$

On an RTX 4060 with 272 GB/s of memory bandwidth running a 7B parameter model in Q4_K_M quantization (4.8 GB weight size):

$$T_{\text{max}} = \frac{272}{4.8} \approx 56.6 \text{ tokens/sec}$$

flowchart TD
    subgraph VRAM Allocation Bounds (8192 MB Max)
        Weights[Model Weights Buffer: 4,200 MB - 5,200 MB]
        CUDA[CUDA Memory Context: 800 MB]
        KVCache[Dynamic KV Cache Pool: 1,500 MB - 2,500 MB]
    end
    
    Weights --> VRAMCheck{Total Memory < 8192 MB?}
    CUDA --> VRAMCheck
    KVCache --> VRAMCheck
    
    VRAMCheck -- Yes --> HighSpeed[Fast GDDR6 VRAM Execution: 45-65 tok/sec]
    VRAMCheck -- No (Spillover) --> PCIebus[PCIe Bus System RAM Offload: 3-5 tok/sec]

Master Benchmark Matrix: Top Open LLMs for 8GB VRAM

All models were evaluated on an NVIDIA GeForce RTX 4060 (8GB VRAM, GDDR6) running Ollama v0.5.7 on Linux kernel 6.8 with CUDA 12.4.

RankModel IdentifierActive ParamsQuantizationVRAM Usage (4k Ctx)Decode Speed (tok/s)HumanEval ScoreOverall Benchmark Score
1qwen2.5-coder:7b7.6BQ4_K_M4.7 GB54.2 tok/s84.1%9.4 / 10
2deepseek-r1:8b8.0BQ4_K_M5.2 GB42.8 tok/s79.2%9.2 / 10
3llama3.1:8b8.0BQ4_K_M5.1 GB48.6 tok/s72.6%8.9 / 10
4phi4-mini:3.8b3.8BQ8_04.1 GB78.4 tok/s69.4%8.7 / 10
5gemma2:9b9.2BQ4_K_M6.1 GB31.2 tok/s74.8%8.5 / 10
6mistral-nemo:12b12.2BQ3_K_S6.8 GB22.5 tok/s68.1%8.1 / 10

Detailed Model Breakdown & Deep Dives

1. Qwen 2.5 Coder 7B (Best Overall for Developers)

Alibaba’s qwen2.5-coder:7b is the undisputed leader for 8GB VRAM consumer cards. Outperforming many 33B and 70B parameter models from previous generations, it scores 84.1% on HumanEval.

  • VRAM Footprint: 4.7 GB in Q4_K_M, allowing up to 16k context window expansion before reaching memory limits.
  • Key Advantage: Supports repo-level code understanding, FIM (Fill-In-the-Middle) completion, and multi-file code editing inside VS Code and Cursor.
# Pull and run Qwen 2.5 Coder 7B in Ollama
ollama run qwen2.5-coder:7b

2. DeepSeek R1 8B (Best Local Reasoning Model)

Built on top of Llama 3.1 8B via RL distillation, deepseek-r1:8b brings step-by-step reasoning capabilities to 8GB GPUs.

  • VRAM Footprint: 5.2 GB in Q4_K_M.
  • Reasoning Overhead: Because it emits intermediate <think> chain-of-thought tokens, total prompt turnaround time is longer than standard dense models, but factual accuracy on logic and math tasks is significantly higher.
# Execute local reasoning prompt
ollama run deepseek-r1:8b "Write a Python function to solve the N-Queens problem using backtracking."

3. Phi-4 Mini 3.8B (Best Speed & Low Latency)

Microsoft’s phi4-mini:3.8b achieves 78.4 tokens per second decoding throughput on 8GB GPUs by leveraging synthetic data curation and efficient 3.8B parameter architecture.

  • VRAM Footprint: 4.1 GB even in high-precision Q8_0 quantization.
  • Key Advantage: Near-instantaneous initial Time-to-First-Token (TTFT < 80ms), ideal for local auto-complete extensions and real-time agent loops.

Context Window Spillover & Memory Threshold Analysis

Extending context window length increases KV cache allocation. The table below shows total VRAM consumption across context sequence lengths ($C$) for an 8B parameter model (Q4_K_M):

$$\text{KV Cache Size (MB)} = \frac{2 \times L \times H \times D \times C}{10^6}$$

Context Sequence LengthWeight MemoryKV Cache MemoryTotal VRAM RequiredPerformance Status
2,048 tokens5.1 GB0.4 GB6.3 GBFast GDDR6 Execution (48 tok/s)
4,096 tokens5.1 GB0.8 GB6.7 GBFast GDDR6 Execution (46 tok/s)
8,192 tokens5.1 GB1.6 GB7.5 GBNear VRAM Limit (44 tok/s)
16,384 tokens5.1 GB3.2 GB9.1 GB (Spillover)PCIe Throttling (4.2 tok/s)

Optimization Tip: When serving 8B models on 8GB VRAM GPUs, set num_ctx: 8192 in your Ollama configuration to prevent system memory spillover.


Summary & Recommendation Guide

  1. For Code Generation & IDE Integration: Deploy qwen2.5-coder:7b.
  2. For Logic, Math & Reasoning: Deploy deepseek-r1:8b.
  3. For High-Speed Chat & Agentic Loops: Deploy phi4-mini:3.8b.

Frequently asked questions

Why does inference speed drop drastically when a model exceeds 8GB VRAM?

When model weights and KV cache memory exceed available GPU VRAM, the operating system offloads excess memory blocks to System RAM over the PCIe bus. System RAM bandwidth (30–80 GB/s) is roughly 5 to 10 times slower than GDDR6/GDDR6X VRAM bandwidth (280–504 GB/s on consumer GPUs like RTX 4060 and RTX 3070), causing token generation speeds to drop from 55+ tok/sec down to 3–5 tok/sec.

Which local model offers the best coding performance on an 8GB VRAM GPU?

Qwen 2.5 7B Coder in Q4_K_M quantization is the top-performing coding model for 8GB VRAM GPUs. It occupies roughly 4.8 GB of VRAM, leaving 3.2 GB of headroom for an 8k context window, while scoring higher on HumanEval benchmarks than older 13B and 33B models.

Is Q4_K_M or Q5_K_M better for 8GB GPU execution?

Q4_K_M is the optimal choice for 8GB VRAM cards. While Q5_K_M offers marginal perplexity gains (~0.05 reduction), it increases model file size by ~1.1 GB. This extra VRAM footprint restricts maximum context sequence length before PCIe spillover occurs.

Sources & references

  1. [1]NVIDIA RTX 4060 Hardware Architecture Specs
  2. [2]Qwen 2.5 Technical Report & Coding Benchmarks
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