You’re more likely going to need an ATX power supply. That’s unless the case manufacturer specifically states you use an SFX one. Modular Design

I recommend getting a fully modular PSU since it offers total control of your build’s cable management. Efficiency Rating Most gaming builds will need power ranging between 450 to 650 watts unless you use a powerful GPU like the recently released RTX 4090. ATX 3.0 is the new specification standard for PSUs. This new design adds a new PCIe 5.0 connector with 12 + 4 pins alongside the usual 6 or 8-pin connection. I presume you already have the estimated total wattage that your PC will draw, and an 850W PSU is the ideal power supply unit to complete the build. A 120mm rifle bearing fan with a specially calculated fan curve keeps fan noise down, even when operating at full load.The Corsair RM850x power supply is highly regarded by most builders. It’s fully modular and has an 80+ Gold efficiency rating. Once you have decided on the form factor and modular design, the next thing you need to consider is the efficiency rating you can afford.

Almost all PSU manufacturers design PSUs with the 80 Plus efficiency rating certification. The “80 Plus” rating system is the industry standard! DC-DC Converters: 2x UBIQ QM3054M6 (30V, 61A @ 100°C, 4.8mOhm) & 2x UBIQ QN3107M6N (30V, 70A @ 100°C, 2.6mOhm) PWM Controllers: uPI SEMI uP3861P My favorite feature about it is the zero RPM fan mode that offers near-silent operation at low to medium loads. Pros: Semi-modular PSUs have only the most important cables attached, with room to add extra cables as needed. Simply put, an 850W 80 Plus PSU will draw a maximum of 1,062.5W at 100% load, which means less wattage is wasted as heat in the conversion process, saving your energy bill.

ZERO RPM FAN MODE

The 80 Plus Gold efficiency rating is usually the sweet spot for most gaming PC builds. Anything above this is overkill and quite expensive! ATX 3.0 Compatible