Intel processor memory limits, enabling XMP

[bevo1981]

on Intel's site they list all the specs for their processors, and for memory it will list either DDR4 or DDR 5 and then "up to ........ MT/s".   so my question is what happens if you install memory sticks that exceed that frequency limit?  for instance, the i5 has a DDR5 stated limit up to 4800MT/s.  so if you install 5600MHz sticks are they just automatically throttled down to that CPU's stated limit of 4800?  does enabling the XMP simply tell the system to ignore the CPU's limit and actually run the memory at their full frequency?

[Dr0idGh0sT]

It's not CPU's limit, it's what they can support without enabling XMP. So you should always buy faster RAM and enable XMP, for Intel at least 6000MHz. 

[RONOTHAN##]

11 minutes ago, bevo1981 said:

so my question is what happens if you install memory sticks that exceed that frequency limit?

They run at whatever the JEDEC spec the motherboard decides is warranted based on the CPU, DIMM config, and what the DIMM's rated JEDEC speed is (you can have it where a 12600K will boot 5600MT/s JEDEC, but that's not super common), then if you enable XMP it should in theory run at the rated clock speed. The CPU's rated limit is more for RMA purposes than it is an actual limit, since pretty much every Intel CPU will be able to exceed the rated speeds pretty significantly. My 13700K, for instance, is rated at DDR5 5600 and DDR4 3200, though I have gotten it to run benchmarks at DDR5 8400 and DDR4 4000 before. Do know however that the Intel memory controllers vary from chip to chip pretty significantly, where you can get a chip that cannot do DDR5 7200 stable, while you can find one that does DDR5 8266MT/s fully stable on 4 DIMM motherboards at XMP. 

 

11 minutes ago, bevo1981 said:

does enabling the XMP simply tell the system to ignore the CPU's limit and actually run the memory at their full frequency?

More or less. It also says to use the rated timings of the kit and whatever voltage it wants in order to work.