XMP profiles use a pre-defined set of parameters that are actually built into the JDEC chip on newer memory. When a XMP profile exists, it often allows the memory to run at or above its rated SPD speed and default voltage. It can also work in conjunction with turbo boost and CPU stepping to enhance performance.
There are a lot of things that come into play when you have to make manually settings. Your BIOS rev, CPU and memory dictate what may or may not work. Some RAM, even if on the QVL for a board requires that the CPU and it be overclocked for the system to run stable.
You typically disable XMP when setting your memory manually since this is not dynamic in nature. When you have a system that won't POST, many have been successful setting memory parameters manually using just one stick of RAM, then making adjustments till the right combination is found. What I'm saying is.. there is no magic pill for this, one setting that guarantees compatibility. You may have to spend some time messing with it, or just buy 1600Mhz RAM and call it a day. Your 4th gen Devils Canyon 4690k CPU is friendly to this, but Kingston sometimes does weird stuff with their memory, like making its default SPD above the "standard" default clock speed of "like" DIMMs.
I walked away and posted after dmdilks.. but as you can see, we both think alike