Yeah! A stick of 5600 can generally reach 6000 with geardown off and that’s as far as I’ve seen cause to dial it. But certain parameters that are popular to lower for latency reduction can be, how would I put it, slightly less flexible — tREFI comes to mind as one that nearly any lowering of (on the enterprise sticks I’m using anyways) tends to cause DFE/MBIST training failures no matter what, even with direct airflow, before it ever boots far enough for memtest to expose ECC errors.

(For those out there following along with PCs, if you aren’t tuning with MBIST maxed out in your BIOS, you might want to revisit that.)