Intersting, on Twiotter somebody posted a retail ASRock X670E Steel Legend motherboard, which has a sticker covering its four DDR5 DIMM slots. The sticker has some info on the ideal DIMM slot selection for dual-channel memory (4x sub-channels); but what catches our eye is a table that states just how long the motherboard will take to train the memory.

At initial boot up, or after a clear-CMOS operation (where your BIOS settings are erased) you'll need to wait a while. The table shows that training two 16 GB modules (1 DIMM per channel/1DPC) takes 100 seconds (or until first boot). Two 32 GB modules (1DPC dual-rank) take 200 seconds, as do four 16 GB modules (four single-rank modules in a 2DPC configuration). Four dual-rank modules in a 2DPC arrangement take about 7 minutes to train. 100 to 400 seconds with a dark screen or no display signal is enough to unnerve anyone.

Since UEFI BIOS upgrades clear CMOS, you'll have to wait hundreds of seconds before the display lights up to confirm the update. Memory overclocking (which includes dozens of reboots and retraining memory) doesn't take hundreds of seconds until you clean CMOS.

Worst case scenario, that's ... over 6 minutes.