Selling an open-box modded NVIDIA GeForce RTX™ 4090 48GB blower-style graphics card. I purchased several of these GPUs for my engineering design studio, Kaifuku Labs, then updated one machine to an RTX PRO 6000, so this unit is surplus. The card was installed only to verify it was not DOA and to run basic testing. It is otherwise considered open-box.

For memory-bound AI and rendering workloads, a modded RTX 4090 48GB is a practical alternative to an RTX 5090. The 5090 is faster in raw benchmarks, but its 32GB VRAM ceiling limits local LLMs and batch generation. A 48GB RTX 4090 gives you 16GB more usable VRAM, lets you run Llama 3.3 70B Q4_K_M, Gemma 4 31B, and Qwen3 32B without CPU offloading, and pairs with a second card for 96GB effective VRAM — matching an RTX PRO 6000 Blackwell at a lower entry cost. I run that exact pairing: two worker nodes on RTX 4090 48GB cards for parallel rendering, LLM inference, and Stable Diffusion/ComfyUI batches, plus a third node on an RTX PRO 6000 96GB for workloads that cannot be split across cards.

Per the modification lab, this model features a GeForce RTX 4090, 48GB GDDR6X, 450W TDP, 1x 12VHPWR power connector, PCIe 4.0 x16, 3x DisplayPort 1.4, 1x HDMI 2.1, and a blower-style cooler the same size as NVIDIA A100 / A6000 GPUs.

Condition

Functional: Open-box and tested only to verify the card was not DOA. Installed briefly for basic testing/benchmarking with no known functional issues. Validated with PyTorch, LLM/diffusion workloads, GPU Burn, FurMark, and Vulkan MemTest.

Cosmetic: Open-box condition. The plastic protective cover is still attached; any visible marks in the photos are on the film, not the GPU. The GPU itself is in pristine condition.

Technical Notes

Modified 48GB RTX 4090 built on a full-power AD102-300/1 core using generation 3 PCB. BGA rework uses Stirri flux followed by ultrasonic cleaning. Memory bandwidth remains stable around 900 GB/s (+/- 6%).

Included

• One modded NVIDIA RTX 4090 48GB blower-style GPU

Power Requirement

This card has a 450W TDP and requires a compatible 12VHPWR power connection.

Buyer must use the correct 12V-2x6 / 12VHPWR cable or adapter supplied by, or specifically approved by, their PSU manufacturer for their exact PSU model. Do not mix modular PSU cables between brands or PSU models.

Buyer Notes

• Sold exactly as pictured and described.
• Confirm case clearance, PSU compatibility, and power cable compatibility before purchasing. The blower-style cooler is best suited to server cabinets, racks, basements, or dense compute environments where blower noise is acceptable.
• For fraud prevention and shipment verification, all item serial numbers are recorded and logged prior to shipment.
• Item condition and packaging are photographed/recorded before shipment to help prevent shipping or return disputes.
• Any disassembly, cooler removal, BIOS flashing, or physical alteration after delivery is the buyer’s responsibility.

Packing / Shipping

The GPU will be placed in a 3-mil static shielding bag, then inside a static shielding ESD foam mailer. That assembly will go inside a double-wall corrugated shipping box with foam to prevent movement during transit. Shipping is insured via a tracked carrier with signature confirmation required.

References

• GPU Labs technical info
• Validation video
• Fan noise under load

Tags

NVIDIA, RTX 4090, 48GB, modded GPU, GPU Labs, blower, GDDR6X, AI, LLM, workstation, RTX 5090, VRAM, AD102, ComfyUI, Stable Diffusion, Blender, OctaneRender, DaVinci Resolve, PCIe 4.0