Enable XMP or DOCP before you do anything else.

Yes, you have to turn it on manually. RAM doesn’t run at its advertised speed out of the box — it defaults to a safe JEDEC speed (usually 2133 or 2400 MHz) until you tell it otherwise.

Getting into BIOS is the same as always: mash Del or F2 while booting. The setting is usually under “Ai Tweaker” on Asus, “OC” on MSI, or “Memory” on Gigabyte. On Intel boards it’s often listed as XMP (Extreme Memory Profile). On AMD boards it might be called DOCP or EOCP — same thing, different branding.

Pick the profile that matches your RAM’s rated speed (usually Profile 1). Save and exit. Your machine might take an extra boot cycle or two while it trains the memory. That’s normal. If it doesn’t POST, clear CMOS and try again, or drop to a slightly lower speed.

It takes two minutes and wakes up the performance you paid for. You’d be leaving 10–20% on the table otherwise.