Background (simplified):
When any computer starts up the BIOS reads the SPD tables programmed into the memory. You can download and run CPU-Z to see the SPD tables in your memory. The BIOS then uses the memory speed and memory timings from the SPD tables that corresponds to the CPU speed that is set in the BIOS.
XMP profiles were developed to allow automatically setting not only memory speed and timings automatically, but also memory voltage. So, with the added ability to increase voltage, memory manufacturers could program SPD tables that run the memory even faster with the higher voltages available, and do that automatically too.
But the whole concept of XMP is faulted because the person writing the XMP SPD table for the memory has no idea what motherboard, CPU, what other peripherals are connected to your motherboard, nor even how many memory sticks you have installed. So, XMP profiles are just a guess at what memory overclock will work for the widest range of motherboards, CPUs, memory, and computer configurations. They have nothing to do with what your specific setup is. ... they're just a guess.
Do they work? Sometimes, sometimes not. And even if they do work it is unlikely they are the best settings for you particular setup.
Memory setting (with or without overclocking) is best done by manually setting the memory settings in the BIOS.
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Do the math:
Memory latency, or timings, like the number 10 in CL 10, are the length of time it takes the memory to complete a step in what it has to do. That "time" is measured in "clock ticks" (1T = 1 clock tick), ie CL 10 takes 10 clock ticks to complete before the memory can move on to it's next operation. The length of one clock tick is the speed at which the memory is running. 1800 MHz memory has a clock tick length of one 1,800,000,000th of a second (1,800,000,000 clock ticks per second), so the CL step takes 10 x 1/1,800,000,000 seconds.
A stick of memory always takes the same amount of time to complete it's CL step (or any other step) no matter what speed it is running. If you run the above memory stick faster, say 2400 MHz, it still takes 10 x 1/1,800,000,000 seconds to complete the CL step, but each clock tick is now 1/2,400,000,000 of a second, so it now would take more clock ticks to complete the CL step. Namely, 24/18 times 10 (for CL step) or 13.3 clock ticks (10 times 24/18 clock ticks). But, alas, that has to be rounded to to CL 14 as memory can't use partial clock ticks.
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