XMP or Extreme Memory Profiles, is an Intel technology that allows you to change multiple memory settings by simply selecting a different profile, taking advantage of higher than standard memory speeds. If you’ve ever wanted to overclock your memory but didn’t want to fiddle with frequency, voltage and timings, this is the way to do it.
How it works
When you power on your computer, it conducts a power-on self-test. Part of this process includes automatically configuring installed hardware, including your memory. Your computer needs to know the model of your RAM as well as which timings and frequency to set. Your BIOS will use a small chip on your RAM modules called an SPD (serial presence detect) chip to set memory timing and frequencies properly. XMP is an extension of SPD which provides higher frequencies and tighter timings for your memory to run at. It also corrects for the extra voltage required which provides a stable overclock with the click of a button.
XMP profiles essentially allow high-performance RAM, which run above industry DDR specifications, to be appropriately set for your system.
Which button to click and where
XMP profiles can be accessed from within the BIOS on supported motherboards. Supported memory modules contain two different XPM profiles which provide different levels of overclocking. Simply select one of the two profiles, save your settings and reboot. You can confirm your new overclock using a program such as CPU-Z.
What if I don't turn on XMP?
All high-performance RAM uses XMP profiles, because they all run above standard DDR industry specifications. If you don't enable XMP, they will run at your system's standard specifications that are dependent on the CPU you have. That is to say, you won't take advantage of the higher clock speeds that your RAM may have.
In most circumstances, this will be fine. Your system will simply run to spec, and you can rest easy knowing everything is nice and stable. However, XMP allows your system to set motherboard and CPU parameters correctly, to allow higher frequency RAM modules, that are designed to run beyond usual specifications.
Why are there two profiles?
XMP supported modules contain two memory profiles labeled "Profile 1" and "Profile 2". The first profile contains enthusiast settings; these allow your memory to run at the rated speed advertised on the box. These settings enable only a modest overclock and are also the most stable. The second profile contains more extreme settings that offer a much higher level of performance. Having two profiles allows you to quickly change performance levels for benchmarking or resource heavy tasks.
Is XMP stable?
Any time overclocking is involved, there is a risk of instability. With XMP the configurations included are thoroughly tested for the specific memory you are using. The timings, voltage and frequency are set to compliment each other and mitigate much of the instability that can creep up with a manual overclock. No automatic configuration can account for outside factors such a CPU overclock. This is something to keep in mind if you experience any instability.