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#31
XMP is a certified OC over a base memory speed.
For what I know, all DDR4 memory have a base memory speed of 2400MHz and DDR3 have a a base memory speed of 1600MHz
My DDR4 is rated as 2400MHz and under XMP it's overclock to 3000MHz.
Over clock side effect is ALWAYS a over voltage that leads to higher temperatures.
Don't use higher OC than the XMP certified OC. You may ruin it.
Depends on RAM in question. Most DDR4 starts at 2133 MHz, is certified to work up to XMP profile top frequency and only above that can be considered an OC.
Most DDR3 starts at 1066MHz, SPD/XMP certified to what it can actually do. Max I have seen as 2400MHz but most go 1600-1866MHz.
There's another component to memory and that's IMC (Internal Memory Controller) that is located in modern CPUs. It's frequency has to match RAM frequency. 2rd gen Ryzen is somewhat different, has an IO module separate from cores in same package and doesn't have to match RAM frequency, could be adjusted separately and it's made in 14nM technology while cores are 7nM.
AMD calls it FCLK and some say that higher FCLK frequency helps with RAN performance for RAM 3000MHz or less, for any higher than that it has to match RAM's base frequency. For instance of you run RAM at 3000MHz, it's base frequency is 1500MHz because it's DDR (Double Data Rate).
Double Data Rate means that it uses signal voltage as it rises and falls in the square wave which is at base frequency.
Mike, On my Gigabyte Z170, on the memory specifications it says that everything above 2400 MHz is considered OC
Support for DDR4 3866(O.C.) / 3800(O.C.) / 3733(O.C.) / 3666(O.C.) / 3600(O.C.) / 3466(O.C.) / 3400(O.C.) / 3333(O.C.) / 3300(O.C.) / 3200(O.C.) / 3000(O.C.) / 2800(O.C.) / 2666(O.C.) / 2400 / 2133 MHz memory modules