NZXT C1200 ATX3.1 is recommended.

I use the ASUS TUF Gaming 1200W Gold. Workd well.

Just saw this thread and tbh wattage is only half the battle when u start looking at cards this beefy. Before deciding on a unit, what case are u actually planning to put this in? I'm a bit concerned about physical fitment and airflow more than just the raw power draw. Not 100% sure but I think we need to consider:
* ATX 3.1 compliance for handling those crazy microsecond transient spikes
* The physical length of the PSU (some 1200W+ units are super long and might hit ur drive cages)
* Side panel clearance for the 12V-2x6 cable so it doesn't get a dangerous bend IIRC the 5090 is rumored to have a massive footprint, and if the PSU doesn't have enough room for clean cable management, ur basically going to have a nightmare getting the side panel back on. What's the rest of the build looking like?

NVIDIA recommends a 1000W PSU for the RTX 5090, which has a total graphics power (TGP) of 575W. This recommendation provides a baseline, but it's crucial to consider your entire system's power needs. If you're pairing the RTX 5090 with a high-end CPU or planning future upgrades, opting for a PSU with higher wattage, such as 1200W or more, can offer additional headroom and stability.

1200W is recommended.

Honestly, I'm gonna have to disagree with the "1200W or bust" mentality that seems to be the trend here. Tbh, if you look at real-world stress tests and community reviews on these high-end setups, a top-tier 1000W unit handles transient spikes just fine as long as it's a solid platform. My biggest caution tho is don't just buy a high wattage unit and think ur safe. I've seen way too many people in the enthusiast community focus on the 1200W label while ignoring the actual build quality of the 12V-2x6 cable that comes in the box. Basically, you're better off with a legendary 1000W unit than a mediocre 1200W one that has cheap pins. Check the community-run PSU tier lists before you drop cash, because the "official" specs from manufacturers can be pretty misleading when it comes to actual sustained loads vs. marketing hype. Just make sure those connectors are seated all the way in or you're gonna have a bad time regardless of the wattage.

An 850W high-quality PSU is likely sufficient for an RTX 5080, with 1200W offering more headroom for a 5090 or future upgrades. Prioritize PSU quality over sheer wattage for long-term reliability.

1000W is OK.