TehPenguin :
gskill support :
The CPU can handle DDR4-3400+, it depends on the motherboard and your ability to set up UEFI. If you purchase qualified hardware, reaching that extreme frequency can be as easy as enabling the XMP Profile in UEFI.
Can you elaborate on that a bit? Because "...[it] can be as easy as enabling the XMP Profile in UEFI." sounds fairly complicated to me. I was eye-balling the G.Skill 32GB, DDR4-3200, CL14-14-14-34 and also started wondering if I can even benefit from that. i7-6700k and ASUS ROG Maximus VIII Ranger MoBo.
Don't bash me for reviving an ancient thread, please. I already feel bad for it but still desperate enough to do it.
In the BIOS/EFI, there is an option to enable XMP Profile. For the ASUS motherboard, it is the very first option in the AI Tweaker page to adjust CPU and memory settings, 'AI Overclock Tuner'. Set this value to XMP Profile and that will allow the motherboard to automatically detect and configure settings for the RAM to operate at the rated specifications. Without doing this, the system defaults the RAM to DDR4-2133 as a standard boot up value. Another method you can use to set up the system to run at maximum performance is by manually inputting the DRAM Frequency, timings, and Voltage that you see on the RAM and packaging. This is essentially what the XMP Profile does for you, but you can also input them manually.
Considering you are using a certified motherboard and capable CPU, XMP Profile should work without a glitch. If the motherboard is not officially certified, you may need to manually input settings, and in some cases you may not be able to reach the full specifications of the RAM. Many motherboards state DDR4-3400+++ but there are actually no tested kits capable; essentially it is a rating of the Z170 chip set, but the quality of components or BIOS is not fully capable of achieving the extreme value just yet. So when building an extreme performance desktop, it is important to use a certified motherboard, RAM, and CPU for optimal performance. The G.Skill QVL list can be found on the gskill.com website in the product page of each memory model. You can also determine validation results using the G.Skill RAM Configurator. Always research to see or ask manufacturers about combinations that have been tested capable of your desired target/need.
Skylake does scale very well with high DRAM Frequency. Results may vary depending on test, application, software, and hardware. For high bandwidth needs, high DRAM frequency will always be better. For most users DDR4 dual channel is years beyond their need, but for professionals and those that require maximum processing power, maximum bandwidth is ideal for their need.