Yo! Jumping in here because I'm basically in the same boat—I just finished my first big build and was SO paranoid about safety. With a 4090 and a 14900K, you're looking at some serious power draw, especially when that CPU starts boosting during your 4K edits! Ngl, I think going with 1200W or more is totally the right move just to be safe. For your situation, here is what I recommend: 1. **Handle the Spikes:** I'm still learning about this stuff, but I read those 4090s have "transient spikes" where they pull huge power for a tiny second. A bigger unit like the MSI MEG Ai1300P PCIE5 1300W 80 Plus Platinum handles that way better than a 1000W unit ever could.
2. **Monitoring Power:** This model actually lets you check your wattage in real-time through software. It's so cool and helps me feel way safer seeing exactly what's happening!
3. **Noise:** Since it's high wattage, the fan doesnt have to spin as fast. It basically stays silent during lighter tasks! I went with a big unit and it feels so much safer. Tbh, do you think you're gonna be doing any crazy overclocking?? Anyway, it's gonna be an amazing build!! 👍

For your situation, I’d seriously jump to 1200W just to be safe. I’m super satisfied with the Corsair RM1200x Shift 1200W ATX 3.1 Power Supply—it’s cost-effective and has great side connectors. Alternatively, the MSI MPG A1000G PCIE5 1000W 80 PLUS Gold Power Supply is cheaper, but honestly, 1000W feels risky with those 14900K power spikes. Meeting the ATX 3.1 standard is key for those transient loads. Better to spend a little more now for stability lol.

oh man, congrats on that dream build!! honestly i'm so excited for you cuz that combo is gonna be absolutely amazing for 4K editing! i've been building rigs for like 10 years now and i've learned the hard way that skimping on the PSU is a HUGE mistake, especially with those crazy transient spikes on the 4090. i'm still kinda figuring out all the new ATX 3.0 specs myself, but here is what i found after looking at basically every review: 1. Corsair RM1000x Shift 80 PLUS Gold Fully Modular ATX Power Supply - a buddy of mine uses this and it's super quiet. the side-mounted cables are actually really cool for cable management, but 1000W felt a bit tight to me for a 14900K? idk but it's a great mid-range choice!
2. Seasonic Vertex GX-1200 1200W 80+ Gold ATX 3.0 - this is actually what i ended up buying for my own rig!! it's fantastic. it has the native 12VHPWR cable so no messy adapters, and the zero-RPM mode is seriously silent. i havent had any coil whine at all, which is a big win!
3. be quiet! Dark Power Pro 13 1600W 80 PLUS Titanium - if u want the absolute best and have the budget, this is basically the king. it's 1600W so it's total overkill, but it's titanium rated so it's super efficient for those long 4K rendering sessions. tbh i really think 1200W is the "safe" sweet spot for u. 1000W might work, but since ur doing heavy video work, that 14900K is gonna be sucking down TONS of power... so yeah, 1200W gives u that extra breathing room so u dont have to worry about random shutdowns! good luck with the build, it's gonna be a beast!! 👍

sooo I went through this exact same headache last year... basically had the same parts list and was sweating bullets over the power draw. Ngl, the 14900K is a literal furnace when it's boosting, and those 4090 transient spikes are no joke. I remember reading all the technical deep-dives on load regulation and just feeling super anxious about whether a standard unit could actually keep up without tripping OCP. In my case, I actually started by looking at 1000W units because on paper the math works, but I'm pretty conservative when it comes to system safety. I ended up deciding to jump to a 1200W ATX 3.0 model instead. Honestly? The peace of mind alone was worth it. Because I'm not maxing out the total capacity during 4K video exports, the fan stays in that zero-RPM mode way longer, which totally solved my noise concerns. One thing I learned the hard way is to be really careful with the 12VHPWR cable clearance. My current setup uses the native cable that came with the unit, and it's way cleaner than the adapter, but some of those stock cables are still pretty stiff. I had to be super cautious not to bend it too close to the connector. If you're doing heavy editing, you'll likely be hitting both the CPU and GPU hard at the same time, so having that extra headroom just feels safer for the long haul, you know? gl with the build, it's gonna be a beast!! 👍

Just catching up on this thread and honestly, building a beast like this yourself is the only way to go. I used to let shops handle my high-end rigs but after seeing how some pros just cram cables in or use whatever unit they have overstock on, I started doing everything myself. When youre dealing with a 4090 and a 14900K, you really want that hands-on control over the components and the cable routing. I went through a whole phase of testing different units because I was obsessed with getting it perfect. Tbh, if you stick with the top-tier lineups from a brand like Seasonic or maybe even Super Flower, you basically cant go wrong. I've always felt like those guys really over-engineer there stuff for DIY enthusiasts who actually push their hardware to the limit. Well actually, I think Super Flower is one of those sleeper brands that people forget makes the internals for half the other big names anyway.

• Just get any high-wattage unit from Seasonic
• Go with something from Super Flower if you want rock solid internals
• Look at the premium lines from EVGA Doing the work yourself for that native 12VHPWR connector is actually pretty satisfying too. It makes the build look so much cleaner than those messy adapters. Good luck with the build, its gonna be a monster!