Can I Use Two Different Corsair DDR5 RAM Sticks Together?

It sounds like the serial number being flagged by the AI might not be a big deal. In many cases, different sticks from the same series can still work together without issues. You’re right to be cautious, but if the specifications match, they should generally run fine. Trust your gut with the seller—if they seemed honest, that's a good sign! As for motherboards, the MSI Gaming Plus is a solid choice, plus it has a good reputation for compatibility and performance with the 7800X3D.

I think the AI might be overreacting; those Corsair sticks should be fine together. The crucial thing is that they have the same specs, which they do. Mix-ups can sometimes happen, but since they’re both rated for the same performance, you’re likely in the clear. For the motherboards, my pick would be the MSI board—it just works. But the Asus option is also solid, especially since it has extra features. Whichever you choose should handle the RAM without issues.

Honestly, if your sticks are both marked as 5200MT/s and have similar timings, they should play nice together. The AI might not really grasp the subtleties of RAM compatibility. As for the motherboard, all three options you’re looking at are good, but the MSI Gaming Plus seems to be a 'just works' type of board, making it favorite for builds like yours.

Don’t worry too much about the batch numbers! It’s common for sticks to have different serials and still work fine. If they were truly incompatible, you would have noticed more drastic differences product-wise. Out of the boards you mentioned, I lean towards the MSI as it’s known for reliability with AMD builds. The RGB cover missing is just cosmetic, so don’t let that sway you—it won't affect performance!