I recently built a PC with an X870 Plus WiFi motherboard, Ryzen 9 9900X3D, 32GB of Kingston Fury DDR5-6000 CL36, an RTX 5060 Ti 16GB, a 1000W Be Quiet! Platinum modular PSU, and a 2TB WD SSD. The system is stable at default memory settings, but enabling EXPO causes instability. BIOS, chipset, graphics, and other drivers are up to date. I'm wondering whether this is simply a CPU or memory-controller limitation, or if a future BIOS update might improve compatibility. I've also tried lowering the memory speed, but the issue still occurs. Performance is otherwise good, including around 50 FPS in BeamNG at 4K on high settings.
2 Answers
First, double-check that the two memory sticks are installed in the motherboard’s recommended paired slots, usually the second and fourth slots from the CPU. Incorrect slot placement can make EXPO unstable.
Because the 9900X3D usually isn’t heavily affected by memory speed, running below DDR5-6000 should have only a small performance impact. Try enabling EXPO and manually setting the memory to 5600 MT/s, then test stability. If that still fails, the issue may be memory training, BIOS compatibility, or the CPU’s integrated memory controller rather than the advertised RAM speed.
I’ve already tried lowering it as far as 5000 MT/s with EXPO enabled, but it was still unstable. Thankfully, performance is already quite good at the default settings.
They’re installed in the recommended gray slots, A2 and B2.