I had 8 GiB of memory in my HP Pavilion dv7-4110em XE287EA#BED working at 1,066 MHz because one of the 2 4-GiB memory modules had a maximum frequency of 1,066 MHz. Yesterday, I replaced that module with a 4-GiB module which can work at 1,333 MHz. So, now my 8 GiB of memory works at 1,333 MHz...