acer aspire a315-41 has 2666mhz ram but they only work at 2400 mhz !!!

my acer aspire a315-41 rk5u after upgrading to windows 11 shows me in task manager that the ram goes to 2400 mhz instead before doing the upgrade they worked at 2600 mhz.. i installed cpu-z and it tells me the same things as activity manager, then I installed thaipoon burner and it tells me that the frequency is 2666, as further confirmation I typed "wmic memorychip get devicelocator, speed" on the command prompt and here too the frequency is 2666 mhz. but the rams still run at 2400 mhz. maybe it's a problem with windows 11 that blocks the speed of the ram. how do i fix this? I've already gone into the bios and there is no ram setting.