What is the best X870E motherboard for the Ryzen 9 9950X3D?

Honestly if you're going all out for a 9950X3D, I'd go with the ASUS ROG Crosshair X870E Hero ATX. I've used the Crosshair series for years and the VRMs are absolute tanks for heavy workloads. It has the dual PCIe 5.0 M.2 slots and dual USB4 ports you're looking for. It's pricey but worth it for the stability alone imo.

Agreed on the pricing. If you DIY instead of paying a pro builder, the MSI MPG X870E Carbon WiFi is way more cost-effective. You get those dual Gen5 slots without overpaying.

Jumping in here because I've been reading up on the X870E specs lately too. Honestly, I'm not 100% sure which specific model takes the crown yet since they're so new, but I think you should look into the boards that use 8-layer PCBs at the minimum for that 9950X3D. From what I've heard, the signal integrity for dual PCIe 5.0 M.2 slots can get pretty finicky if the board quality isnt top-tier. IIRC, some of the mid-range X870E options are actually packing 18+2+2 power phases which is basically overkill anyway. You might dont need to spend 700 bucks to get the stability you're after. Just watch out for how the lanes are shared... sometimes using that second gen 5 slot might drop your GPU to x8 mode, which kinda sucks for a high-end build. Not sure if that matters for your workload tho, but definitely something to check in the manuals.

Summarizing what everyone said so far... we have the Hero on the table, the 8-layer PCB talk, and the general frustration over those high price tags. Its a lot to weigh up for a high-end 9950X3D build. Quick tip for staying safe: Look at the Gigabyte X870E AORUS MASTER. Gigabyte usually over-engineers their VRM cooling with actual fins instead of just blocks of metal, which is huge for stability during long workloads. Also, ngl, regardless of which board you pick, make sure you manually cap your SOC voltage once you get it running. Early BIOS versions on new chipsets can sometimes be a bit aggressive with the auto settings, and you dont want to risk that expensive CPU. Safety first, honestly.

Ok adding this to my list of things to try. Thanks for the tip!

Literally in the same boat man. Ive been looking for weeks and still havent pulled the trigger because the prices for these high-end boards are getting out of hand. It is honestly frustrating that there isnt more consensus yet since I really need that dual PCIe 5.0 stability for my work too. Hopefully someone actually drops some real-world data soon because I am totally stuck.