NVIDIA GeForce RTX 4070 12GB for FLUX.2 [klein] 4B (FP8 / Q8_0): Local AI VRAM Math & Logen 1.4.0 Settings
Yes. The NVIDIA GeForce RTX 4070 12GB (12 GB VRAM, 504 GB/s bandwidth) runs FLUX.2 [klein] 4B (FP8 / Q8_0) inside dedicated graphics memory on Windows 10/11 x64 and Linux x64. Full-resident peak load is 7.7 GB on Windows (4.3 GB weights + 1.1 GB encoder + 0.8 GB VAE + 1.5 GB OS reserve), leaving +4.30 GB of headroom ([Verified Mathematical]).
1. Hardware & Checkpoint Specification Matrix (12+ Verified Attributes)
High-throughput 12 GB GDDR6X Ada Lovelace desktop GPU delivering 504 GB/s memory bandwidth and 5,888 CUDA cores for rapid local diffusion sampling and 4K tiled upscaling. Compact 4-billion-parameter rectified-flow checkpoint designed for rapid 4-step iteration, low VRAM footprint, and commercial asset production in Logen Pro.
| Attribute | Value | Engineering & Epistemic Notes |
|---|---|---|
| 1. GPU Architecture | Ada Lovelace (AD104) | [Verified] NVIDIA CUDA compute capability for x64 Windows & Linux |
| 2. Dedicated GPU VRAM | 12.0 GB GDDR6/GDDR6X | [Verified] Physical on-card video memory |
| 3. Memory Bus Width | 192-bit | [Verified] Hardware memory interface width |
| 4. Memory Bandwidth | 504.0 GB/s | [Verified] Determines per-step diffusion tensor throughput |
| 5. CUDA Cores | 5,888 | [Verified] Shading & FP16/BF16/INT8 compute units |
| 6. Graphics Card TDP | 200 W | [Verified] Rated board power draw under full load |
| 7. Model Weight File Size | 4.30 GB (FP8 / GGUF Q8_0 compact 4B architecture) | [Verified] Exact disk & VRAM checkpoint footprint |
| 8. Active Text Encoder Footprint | 1.10 GB | [Verified] Prompt encoding buffer (unloaded before sampling in low-VRAM mode) |
| 9. VAE + OS Display Reserve | 0.80 GB VAE + 1.50 GB Win WDDM (0.80 GB Linux) | [Verified] Latent decode + desktop compositor reserve |
| 10. Mathematical VRAM Headroom | +4.30 GB (Win) / +5.00 GB (Linux) | [Verified Mathematical]: 12.0 - (4.3 + 1.1 + 0.8 + 1.5) |
| 11. Fit Verdict State | FITS_IN_VRAM_COMFORTABLE | Sequential offload headroom on Windows: +5.40 GB |
| 12. Recommended Logen 1.4.0 Preset | flux2_klein_txt2img (1024×1024, 4 steps, CFG 1.0) | Logen Pro (£49 one-time license) · Upstream license: Apache-2.0 (Commercial use permitted) |
| 13. Physical Benchmark Reference | Not physically timed on NVIDIA GeForce RTX 4070 12GB (RTX A2000 12GB reference: ~8.0s (4 steps at 1024×1024, ~2.0s/step)) | [Verified Mathematical] Peak VRAM is 7.7 GB on Windows 10/11 (+4.30 GB full-resident headroom; +5.40 GB headroom when ComfyUI unloads the 1.1 GB text encoder before sampling). [Inferred from Memory Bandwidth Ratio] NVIDIA GeForce RTX 4070 12GB provides 504.0 GB/s bandwidth (1.75x the 288 GB/s RTX A2000 12GB reference card timed at ~8.0s (4 steps at 1024×1024, ~2.0s/step)). |
2. Deterministic VRAM Waterfall Breakdown & WDDM Shared Memory Guardrail
Whether FLUX.2 [klein] 4B (FP8 / Q8_0) runs at full GDDR6 speed on your NVIDIA GeForce RTX 4070 12GB or stalls across the PCIe bus into system RAM is governed by exact arithmetic:
- Diffusion Weights (FP8 / GGUF Q8_0 compact 4B architecture): 4.30 GB
- Text Encoder Active Allocation: 1.10 GB
- 1024×1024 VAE Decode & Activation Buffer: 0.80 GB
- Windows 10/11 WDDM Display Reserve: 1.50 GB (Linux x64 reserve: 0.80 GB)
- Net Full-Resident Headroom: +4.30 GB on Windows 10/11 (+5.00 GB on Linux x64)
Why Windows Shared GPU Memory Matters: On Windows 10 and Windows 11, Task Manager displays both Dedicated GPU Memory (12 GB on NVIDIA GeForce RTX 4070 12GB) and Shared GPU Memory (system DDR4/DDR5 RAM). If background apps or an un-evicted Ollama chat model push peak allocation past 12 GB, Windows pages tensors over PCIe and slows generation by 8x to 10x. Logen 1.4.0 prevents this automatically by sending keep_alive=0 to Ollama before ComfyUI starts sampling.
3. Interactive PC & Model Fit Calculator
Calculate Exact Dedicated VRAM Headroom on Windows 10/11 & Linux x64
Select your NVIDIA graphics card, diffusion model, operating system, and target resolution to compute deterministic peak VRAM usage before you download weights.
Formula: Dedicated_VRAM (12.0 GB) – [Weights (6.8 GB) + Encoder (1.2 GB) + VAE Buffer (0.9 GB) + OS Reserve (1.5 GB)] = +1.60 GB available headroom.
4. Exact Recommended Logen 1.4.0 Two-Column Studio Preset
Use these verified studio parameters inside Logen 1.4.0 on 64-bit Windows 10/11 or 64-bit Linux (macOS is not supported):
| Studio Parameter | Recommended Setting | Purpose |
|---|---|---|
| Workflow Pipeline ID | flux2_klein_txt2img | Pre-wired inside Logen 1.4.0 Two-Column Workflow Studio |
| Native Output Resolution | 1024x1024 | Optimal rectified-flow aspect ratio (upscale to 4K via esrgan_upscale) |
| Sampling Steps | 4 | Distilled timestep schedule |
| CFG Guidance Scale | 1.0 | Prevents latent saturation and NaN black outputs |
| Sampler & Scheduler | euler / simple | Deterministic convergence without extra step overhead |
| Text Encoder Residency | Full VRAM Resident | Managed automatically by Logen 1.4.0 runtime |
| Batch Size Limit | Up to 4 images per batch in VRAM (up to 16 sequential in Logen Pro) | Prevents WDDM shared memory spillover |
| Ollama Chat Memory Eviction | Automatic keep_alive=0 eviction before diffusion sampling | Frees 5-6 GB of LLM VRAM before diffusion starts |
5. Compare All Models on NVIDIA GeForce RTX 4070 12GB
| Model Checkpoint | Weights | Win Peak VRAM | Headroom | Verdict State | Logen Tier |
|---|---|---|---|---|---|
| FLUX.1-schnell (GGUF Q4_K_S) | 6.8 GB | 10.4 GB | +1.60 GB | FITS_IN_VRAM_COMFORTABLE | Logen Free (£0 forever) |
| FLUX.2 [klein] 4B (FP8 / Q8_0) (Current Page) | 4.3 GB | 7.7 GB | +4.30 GB | FITS_IN_VRAM_COMFORTABLE | Logen Pro (£49 one-time license) |
| Z-Image-Turbo 6B (INT8) | 6.2 GB | 9.7 GB | +2.30 GB | FITS_IN_VRAM_COMFORTABLE | Logen Pro (£49 one-time license) |
Compare FLUX.2 [klein] 4B (FP8 / Q8_0) Across Other NVIDIA GPUs
| NVIDIA GPU | VRAM & Bandwidth | Full-Resident Headroom | Sequential Offload Headroom | Truth Tier |
|---|---|---|---|---|
| NVIDIA RTX A2000 12GB | 12 GB (192-bit, 288 GB/s) | +4.30 GB | +5.40 GB | [Verified Measured] |
| NVIDIA GeForce RTX 3060 12GB | 12 GB (192-bit, 360 GB/s) | +4.30 GB | +5.40 GB | [Verified Mathematical] |
| NVIDIA GeForce RTX 4060 8GB | 8 GB (128-bit, 272 GB/s) | +0.30 GB | +1.40 GB | [Verified Mathematical] |
| NVIDIA GeForce RTX 4070 12GB (Current Page) | 12 GB (192-bit, 504 GB/s) | +4.30 GB | +5.40 GB | [Verified Mathematical] |
| NVIDIA GeForce RTX 3070 8GB | 8 GB (256-bit, 448 GB/s) | +0.30 GB | +1.40 GB | [Verified Mathematical] |
Running into standalone ComfyUI or Ollama errors? Visit the Local AI & ComfyUI Error Troubleshooting Reference or return to the GPU & VRAM Compatibility Hub.
6. Technical FAQ: NVIDIA GeForce RTX 4070 12GB + FLUX.2 [klein] 4B (FP8 / Q8_0)
Can the NVIDIA GeForce RTX 4070 12GB run FLUX.2 [klein] 4B (FP8 / Q8_0) at 1024×1024 without running out of VRAM?
Yes. The NVIDIA GeForce RTX 4070 12GB (12 GB VRAM, 504 GB/s bandwidth) runs FLUX.2 [klein] 4B (FP8 / Q8_0) inside dedicated graphics memory on Windows 10/11 x64 and Linux x64. Full-resident peak load is 7.7 GB on Windows (4.3 GB weights + 1.1 GB encoder + 0.8 GB VAE + 1.5 GB OS reserve), leaving +4.30 GB of headroom ([Verified Mathematical]). Logen 1.4.0 also evicts idle Ollama chat weights before starting ComfyUI so background LLM allocations do not push the NVIDIA GeForce RTX 4070 12GB into slow Windows WDDM shared system memory.
What are the recommended Logen 1.4.0 studio settings for FLUX.2 [klein] 4B (FP8 / Q8_0) on an NVIDIA GeForce RTX 4070 12GB?
Select workflow flux2_klein_txt2img at 1024×1024, 4 sampling steps, CFG 1.0, sampler euler, and scheduler simple. FLUX.2 [klein] 4B (FP8 / Q8_0) is included in Logen Pro (£49 one-time license) and carries the Apache-2.0 (Commercial use permitted) license.
How fast does FLUX.2 [klein] 4B (FP8 / Q8_0) generate on NVIDIA GeForce RTX 4070 12GB compared to the RTX A2000 12GB benchmark?
[Verified Mathematical] Peak VRAM is 7.7 GB on Windows 10/11 (+4.30 GB full-resident headroom; +5.40 GB headroom when ComfyUI unloads the 1.1 GB text encoder before sampling). [Inferred from Memory Bandwidth Ratio] NVIDIA GeForce RTX 4070 12GB provides 504.0 GB/s bandwidth (1.75x the 288 GB/s RTX A2000 12GB reference card timed at ~8.0s (4 steps at 1024×1024, ~2.0s/step)). Logen 1.4.0 supports 64-bit Windows 10/11 and 64-bit Linux only; macOS is not supported.
Run FLUX.2 [klein] 4B (FP8 / Q8_0) on your NVIDIA GeForce RTX 4070 12GB without wiring ComfyUI nodes.
Logen 1.4.0 installs an isolated Python environment, ComfyUI, and quantized starter weights automatically on Windows 10/11 x64 and Linux x64.