i heard that to install ram 1600 MHz or higher i must have a 3rd generation cpu
like i3 3220 , i5 3570 , i7 3770,......
and i cant install it with cpu like i3 2100 , i5 2500 , i7 2600
is that true?
Can you use the ram? yes. Will it run at the rated speed? no. The memory controller will time the ram at the highest speed it can and that's what you will get. So for some Sandybridge processors, you'll top out at 1333. Others, like the i7 3820, will support 1600. Check the spec sheets at intel for more.