Hello, My laptop have 2 DDR-RAM of each 4GB. Now I want to change one RAM to 8GB. When I checked my RAM in CPUZ then it is showing that DDR-4 2666(1333 Mhz) for both. When I googled it then found both combinedly work as 2666Mhz. Does it means that one RAM have frequency of only 1333Mhz? What if I insert 8GB DDR4 2600 Mhz RAM with 4GB DDR4 1333Mhz RAM? Will it work perfectly. Does after adding that new RAM total frequency will be 3999?