Any RAM actually work on X870E Taichi

You're using A2 and B2 slots, right?

[CPU]-[A1][*A2*][B1][*B2*]

A and B channels are independent.

Does it work with one stick on A2? If it doesn't, that would indicate a problem with A channel. It could be a number of things, like bad contact on one or more pins related to memory A channel. Remember, the memory controllers are inside the CPU and certain pads on the CPU are connected directly to the DIMM slots.

If it works, wow, that's weird. Firmware issue?

One thing I always found crazy is people touching the bottom of the CPU where the pads are. Extremely high frequency signals need to go through a lot of these pads, so any kind of bad contact can cause all kinds of issues (PCIe, DDR, etc.).

But of course, there could be a defect somewhere, too, in the CPU or on the motherboard, etc.

Have you tried re-seating the CPU?

MrFabulous wrote: Any update on this issue? I am also experiencing codes AA and 21 and and need to hard power cycle the system to get it to post.

Same only on the Nova with 9800x3d.

Got 1 stick to work in every channel, but never 2. I tried 2 kits, Gskill and Kingston.
Going to try Corsair, if that doesn't work the mobo goes back to the store.

I've got a Taichi Lite that will post just fine with A2B2 populated, but when I add another pair of the exact same ram to the A1B1, its sits on code 15 for about 5 minutes, then eventually goes to 3E.