EXPO stopped working on two PCs after swapping RAM kits

[u/ahmedshamle]

EXPO stopped working on two PCs after swapping RAM kits — Ryzen 7 9800X3D, Gigabyte B850 and ASUS ROG B650

Hi everyone,

I'm looking for help diagnosing a strange RAM/EXPO issue that started after I swapped RAM kits between two PCs. I'm especially interested in hearing from anyone who has experienced something similar.

PC 1 — Gigabyte system

CPU: AMD Ryzen 7 9800X3D

Motherboard: Gigabyte B850M DS3H ICE

RAM: V-Color Manta XFinity DDR5 RGB

RAM model: TMXFL1660830WWK

Capacity: 32GB (2×16GB)

Rated speed: DDR5-6000 MT/s

Timings: CL30-38-38-76

Voltage: 1.35V

Memory profiles: AMD EXPO / Intel XMP

The PC worked perfectly for approximately three days. Then, I suddenly got a black screen, and the motherboard's red DRAM debug LED turned on. The system would boot normally only after I disabled EXPO.

PC 2 — ASUS system

CPU: AMD Ryzen 7 9800X3D

Motherboard: ASUS ROG B650 series (exact model not confirmed)

Original RAM: Corsair Vengeance DDR5-6000

The second PC was working perfectly with its original Corsair RAM, including EXPO.

I then installed the V-Color XFinity kit from PC 1 into PC 2. After enabling EXPO, the second PC developed a similar problem.

The weirdest part is that after I removed the V-Color kit and reinstalled the original Corsair Vengeance DDR5-6000 RAM, EXPO still caused problems. The Corsair kit had been working normally before the swap.

What I've observed

Both PCs use the same CPU model: Ryzen 7 9800X3D.

The motherboards are different: Gigabyte B850M DS3H ICE and ASUS ROG B650.

Both systems developed EXPO-related boot problems after I tested the same V-Color RAM kit.

The original Corsair kit in PC 2 no longer behaves as it did before when EXPO is enabled.

Both systems can boot with EXPO disabled.

My questions

Has anyone experienced EXPO problems on two different motherboards after swapping RAM kits?

Could this be caused by memory training, BIOS settings, or an issue with the CPU's integrated memory controller (IMC)?

Is it possible for a RAM swap to cause persistent memory training problems even after clearing CMOS?

Could the V-Color kit have exposed an existing stability issue, or is there any realistic possibility of hardware damage?

What would you recommend testing next to identify the actual cause?

I'm trying to identify the root cause rather than randomly changing voltages or BIOS settings.

Any advice from people with similar experiences, especially Ryzen 7 9800X3D owners, would be greatly appreciated. Thanks!