Quick Answer

For a single RTX 5090, an ATX 3.1 Titanium-rated 1,200W PSU is the best choice. For a dual-RTX-5090 workstation, step up to a 1,600W ATX 3.1 Titanium unit. The ASUS ROG Thor 1600W Titanium and Seasonic Prime TX-1600 are the top-tier options available locally at Evetech, both carrying 10-year warranties and native 12V-2x6 cabling.

Single RTX 5090 PSU Requirements 🖥️

The RTX 5090 carries a 575W TDP and connects via a single 12V-2x6 connector rated for 600W continuous. Paired with a Ryzen 9 9950X (around 230W at full Cinebench load), 64GB DDR5, and NVMe drives, the total system peaks at approximately 870W to 950W during a simultaneous CPU and GPU stress event. A 1,200W ATX 3.1 Titanium unit runs this at 72% to 79% load, placing the system firmly in the peak efficiency band. Choosing a 1,000W unit is marginal (87% to 95% load) and risks nuisance trips during transient GPU spikes. A 1,200W minimum is the safer spec for any RTX 5090 single-card build.

Dual-GPU Workstation Power Spec 💼

A dual-RTX-5090 workstation adds 575W for the second card, bringing GPU draw alone to 1,150W at full render load. Add the CPU (a Threadripper 7970X at 350W), memory, drives, and board: total sustained draw during a GPU rendering session reaches 1,550W to 1,650W. This makes a 1,600W PSU the absolute minimum and a 2,000W unit (where available) the safer choice for heavily overclocked multi-GPU configurations. In South Africa, 1,600W Titanium units from ASUS ROG and Seasonic are the highest readily stocked tier, making the ROG Thor 1600W Titanium the practical top choice for dual-5090 workstations locally.

Key Features to Confirm Before Buying 🔧

Beyond wattage and ATX 3.1 compliance, verify these four specifications: first, the unit ships with at least two native 12V-2x6 cables for dual-GPU use (not adapters); second, single +12V rail architecture is confirmed in the spec sheet to avoid multi-rail OCP trips under dual-GPU load; third, full modularity allows cable routing optimisation in large EATX workstation cases; fourth, the unit carries a minimum 7-year warranty (10-year is available on top-tier units). PSUs that tick all four boxes at 1,600W include the ROG Thor 1600W Titanium and the Corsair AX1600i, both stocked or orderable at Evetech.

TIP

Confirm Two Native 12V-2x6 Cables ⚡

When buying a PSU for a dual-GPU workstation, verify the unit ships with two separate 12V-2x6 cables in the box, not a daisy-chain from a single output. Running both RTX 5090s from separate native 12V-2x6 outputs eliminates shared-cable thermal risk and is the only installation NVIDIA formally recommends for multi-GPU setups.

FAQ

Can I use a 1,000W PSU for a single RTX 5090 build?

Not recommended. A 1,000W PSU runs a typical RTX 5090 system at 87% to 95% load, which leaves minimal headroom for transient spikes. During GPU render or extreme gaming scenes the unit may trip OCP, causing crashes. A 1,200W unit provides the right buffer.

Is the ROG Thor 1600W Titanium available in South Africa?

Yes. The ASUS ROG Thor 1600W Titanium is stocked at Evetech. It includes a native OLED power display, dual 12V-2x6 cables, and a 10-year warranty, making it the definitive choice for dual-5090 workstations built locally.

What happens if my dual-GPU workstation draw exceeds 1,600W?

A quality ATX 3.1 1,600W unit will engage overcurrent protection and shut down safely rather than damage components. For builds that regularly sustain above 1,500W, a dedicated server-grade PSU or dual-PSU adapter with two quality units is the engineering solution.

Building the ultimate RTX 5090 workstation in South Africa? Evetech stocks 1,200W and 1,600W ATX 3.1 Titanium power supplies with native dual 12V-2x6 cabling and full local warranty, matched to the power demands of current and next-gen NVIDIA flagships.