What PSU Do You Need for an eGPU Enclosure? Sizing an ATX Power Supply

Modern eGPU enclosures like the Razer Core X V2 arrive empty: no graphics card and, crucially, no power supply, just a bay waiting for a standard ATX desktop PSU. Sizing the right PSU for an eGPU enclosure comes down to matching wattage and connectors to the GPU you plan to run, with enough overhead for the enclosure itself. The bonus is that the same PSU drops straight into a future desktop build, so nothing you buy here is wasted.

Quick Answer

Take your GPU's recommended PSU wattage and add roughly 230W for the Core X V2 enclosure itself, then choose a standard ATX power supply that meets or beats that total. You will connect it with a 24-pin ATX cable and an 8-pin (or 4+4) EPS connector to the enclosure, plus the PCIe power cables your specific GPU needs.

Why eGPU enclosures use a separate ATX PSU

Earlier enclosures shipped with a built-in power supply, which capped the GPUs you could fit and meant a dead PSU bricked the whole unit. The current approach, used by the Razer Core X V2, is a dedicated bay that accepts any standard ATX desktop PSU. That makes the enclosure flexible: you choose a PSU sized for your card, you can upgrade it later, and you can transplant it into a tower if you ever build a full desktop.

It also shifts a real responsibility onto you. The enclosure no longer guarantees adequate power, so getting the wattage and connectors right is now part of the buying decision rather than something handled for you.

Working out the wattage

The calculation is straightforward. Start with the PSU wattage the GPU manufacturer recommends for that card, then add the enclosure's own draw. For the Core X V2, allow an additional 230W on top of your card's requirement, and pick an ATX PSU that comfortably covers the combined figure.

Headroom matters. A PSU running near its rated limit runs hotter, louder, and less efficiently, and leaves nothing for transient spikes that modern GPUs produce under load. Buying a unit with a sensible margin above the calculated total keeps the system quiet and stable, and it leaves room for a more demanding card in future without another PSU purchase.

A worked example

Take a mid-to-upper GPU with a recommended system PSU of around 750W. Add the 230W for the enclosure and you are at roughly 980W of demand, so an 850W unit is too tight and a 1000W or larger PSU is the sensible buy. For a more modest card recommending around 550W, adding 230W lands near 780W, where a quality 850W PSU gives a comfortable margin. Always start from the GPU maker's figure rather than guessing, because it already accounts for the card's peak behaviour.

Connectors: matching the enclosure and the GPU

There are two connection jobs to get right. The first is powering the enclosure's own board. The Core X V2 takes a 24-pin ATX connector and an 8-pin (or 4+4 pin) EPS connector from your PSU, which every standard ATX power supply provides. The second is powering the graphics card itself, and this is where you must check your specific GPU.

Check your GPU's power inputs

Graphics cards vary widely in what they need. Some use one or two 8-pin PCIe connectors, while many current high-performance cards use the 12-pin or 16-pin 12V-2x6 connector instead. Your PSU must supply the right cables, either natively as a modern unit or through the adapter the card includes. Confirm both the count and the type before you buy, because a PSU that physically cannot connect to your card is a frustrating and avoidable mistake. It is worth lining up the enclosure, the PSU, and the card together, and the graphics card range at Evetech shows the current cards and their power needs so you can match a PSU to the one you want.

Why native cables beat daisy-chaining

Where a card needs multiple PCIe power connectors, use separate cables from the PSU rather than one cable with two ends daisy-chained together. Splitting a single cable across a hungry card forces too much current down one set of wires, which is a stability and safety concern on high-draw GPUs. A PSU with enough discrete PCIe cables for your card is the cleaner, safer choice.

Picking the PSU itself

Beyond raw wattage and connectors, a few things make a PSU a good long-term buy. A good efficiency rating means less heat and lower running cost, which matters for a unit that may sit on your desk. A modular design lets you fit only the cables you need, keeping the enclosure tidy. And a reputable unit with a solid warranty protects an expensive GPU from poor power delivery.

Remember the transplant argument throughout. Because this is a standard ATX PSU, it is not a single-purpose accessory. If you later build a desktop, the same power supply moves straight into the case, so it is worth buying a quality unit now rather than the cheapest thing that fits. The enclosure connects to your laptop over Thunderbolt, so it sits alongside the wider docking and connectivity range at Evetech as part of turning a thin laptop into a desktop-class machine.

Who an eGPU setup suits

An external GPU makes most sense for someone with a capable Thunderbolt laptop who wants desktop graphics power at the desk without losing portability away from it. Plug in at home for gaming or creative work, unplug and carry a thin laptop when you leave. The PSU is the foundation of that setup, so sizing it correctly is the difference between a stable, quiet rig and one that struggles under load.

Frequently Asked Questions

What size PSU do I need for the Razer Core X V2?

Take your GPU's recommended PSU wattage and add about 230W for the enclosure, then choose an ATX unit that comfortably exceeds that total. Leaving headroom keeps the system cool, quiet, and stable under load.

Does the Razer Core X V2 include a power supply?

No. It ships without a PSU and accepts a standard ATX desktop power supply in a dedicated bay. You choose and fit the PSU yourself, sized to your graphics card.

Which connectors does the enclosure need from the PSU?

The Core X V2 board takes a 24-pin ATX connector and an 8-pin or 4+4 pin EPS connector, both of which every standard ATX PSU provides. Your graphics card then needs its own PCIe power cables on top.

Can I reuse the PSU in a desktop later?

Yes, and this is a real advantage. Because it is a standard ATX power supply, it transplants directly into a future desktop case, so the purchase is never wasted if you move to a full tower.

Should I daisy-chain PCIe power cables to my GPU?

No, not on high-draw cards. Use separate cables for each PCIe power input rather than splitting one cable. Choose a PSU with enough discrete PCIe cables to feed your card directly for safety and stability.