Z270-K + Corsair vs HyperX vs LED vs Crucial

Faster ram may or may not make any difference, depends on application, the difference between 2400 and 3200 could easily be 0 fps or as much as 20fps, or amounting to several minutes time saved in some apps. That said, there's also no guarantee that higher that 2400 will actually work at its rated speeds without user intervention. To get 3000 to work right might take small bios adjustments or may need a small OC on the cpu, that's where the Memory Controller is located. Or it might work out of the box. That aside, there's other considerations, aesthetics included. Some models are black, some colored, some led. Leds look great, but do nothing for performance, and few ppl care to look at red ram in a black/blue build. Some could care less as they won't see it anyways.

I personally would choose the led, has the most options for an equitable price, and even if it just ran at 2400 stock, it can always be bumped up to its rated 3000 when you do OC.

You really need to look at this in a different way ...

1. Cheapest is a matter of degree. Whether you can get something faster for $10 extra is a very different choice than whether you can get it for $100 extra.

2. The proper judgment here should be based upon the relative increase in system performance as compared with system cost. 16 GB of Corsair 2400 / CAS 16 will cost you $115 - $125 here in US ... at 3200 / CAS 16 you are talking $135 - $145. On a $1500 system, that's a 1.33 % increase in cost Speed increases from faster RAM can range from 0% to 11%, depending on the game in question, what you are measuring (average or minimum) and what system bottlenecks might otherwise exist. here's some recent data

http://techbuyersguru.com/gaming-ddr4-memory-2133-vs-26663200mhz-8gb-vs-16gb?page=3

3. The cost / performance ration right now is that it's pretty easy to justify 3200 ... after that the curve starts to rise sharply and it's harder to justify ... how hard depends upon what you are doing.

4. Heats inks are meaningless .. simply put, buy low profile, the only cooling function of those tall fancy heat sinks is to "look cool".

5. Uninformed folks have been crowing "ooh scary scary" about RAM voltages since Sandy Bridge. There is no issue here. Overclocking bears the inherent risk but with RAM we have a dual standard. JEDEC defined what is and is not OC'ing. The JEDEC standard, IIRC, for DDR-4 is currently at 2400 (don't pay much attention) and the standard dictates the voltage accordingly (again 1.20 IIRC). I don't think about it much as neither I nor most enthusiast give a hoot about what JEDEC says. The only relevant facts with regard to speeds and voltages outside the standard are:

Does the RAM manufacturer guarantee it ? Obviously
Does the CPU manufacturer guarantee it ? Check the Intel **certified compatible** XMP list
Does the RAM manufacturer guarantee it ? Check the MoBo specs

The answer is yes, they all guarantee compatibility at higher speeds and voltages. Nothing else matters.

If you go and see DDR4-5200 @ 1.6 volts on Intel's certified compatibility list than Intel has no basis to claim you violated warranty conditions.

6. The faster the RAM, generally the higher the voltage. As we see here, Intel doesn't have a problem w/ 1.5 volts ... tho starting at at 3200 1.35 (or higher at faster speeds) will typically be the recommended voltage

http://www.legitreviews.com/what-is-the-safe-voltage-range-for-ddr4-memory-overclocking_150115

7. LEDs are a fad that I suspect will be "so last season" in 6 months. I like LEDs when used to illuminate the interior of a box... but the flashy flashy stuff just screams "I'm 13 and ain't I cool".

8. We have never built a box where the RAM that was on any manufacturer's QVL ... not something most enthusiasts ever thing about.

True. All of the above. Don't think I've ever built a pc with the specific ram from a QVL, those are test models mainly and if 1 model works, a different model is gonna work to as model #s change according to everything from color to heatsink, yet use the same IC's.
I like leds when used as accent color, not bling, I'm a long way from 13
Before leds arrived, the heatsink was the 'accent' with oversized heatsinks on ram like the g-skill Rip-Jaws series etc making the biggest statement. Heatsinks don't do much, but they do do a little and a decent heatsink looks a damn site better in an expensive pc than unadorned sticks.

Intel certifies 2133@1.35v (skylake) or 2400@1.35v (kabylake) and thats it. Anything over that is user defined, OC, whatever, as long as the speed rating and voltage apply to the motherboard. You'll not get 3200 to work on a H110 board without a minor miracle.

A little understated accenting quite often goes a lot further than over-the-top bling.

Ask any woman, they know this. Too much makeup = clown (ho), just enuff = (well you get the idea). Case lighting is not really any different.

Think of it this way. Corsair alone has 3 major lines, the Ballistic, Vengeance and Dominators. In each of those lines is 100+ different models, as each color, heatsink, speed, voltage, timing change requires a different model number. So in just Corsair you are looking at somewhere over 1000 different models or better with the minor lines. Now figure that's roughly equal for every other brand, but some like g-skill have 5 or 6 major lines, so you are easily looking at over 50,000 different models. For any manufacturer this would be a monumental task to accomplish, just on one model motherboard, as you figure that each model ram is tested on that mobo using 2-5 different kits. You'd end up with a QVL of well over a million verified models/kits per motherboard. If you figure Asus alone has over 40 different mobo's still in active production, they'd go broke paying ppl to test that many ram sticks.
So they don't. They'll select a few, or get donated a few different models per brand and call it a day, figuring if g-skill 3200 Samsung B work, then 3000 will also, as will 2133 etc. And color or heatsink isn't an issue, just the actual ic's. So out of 50,000 models, 10-15 get tested/certified. If looking at a QVL for 2400 ram and there are 0 Corsair's, safe bet no Corsair will work correctly, if there's a set of Vengeance LPX, safe bet any other LPX model at 2400 will work. No guarantees, but at least a good chance.
Led models are still the exact same ram as non led, they just have fancy lighting on the heatsink. No different than a red heatsink vrs blue.

HX424C15FB2K2/16
That's a Kingston HyperX you listed. It reads like this.
HX (HyperX)
4 (ddr4)
24 (2400 speed)
C15 (Cas 15)
FB2K2 is that particular model number. In that model number is the heatsink, color, kit (2 dimms so it'd be K4 for a 4x? Kit) etc
/16 is the size. (K2 /8 would be a 2x4gb kit, K1 /8 would be a single 8Gb stick)

CMK16GX4M2B3200C16
CMU16GX4M2C3000C15
Same thing. CMK is standard Vengeance, CMU is led, both 16Gb kits of ddr4, one being 3200 C16, the other being 3000 C15.

Intel runs 2133 (skylake) 2400 (kabylake). That's it. Anything over those speeds is considered OC and is entirely on the mobo, nothing to do with Intel other than what Intel defines for their own boards. XMP is nothing more than predetermined settings for timings, voltage, speeds according to the jadec tables. Just saves ppl the hassle of trying to figure out the correct settings for all 30+ timings, voltage etc when moving from 2133MHz to 2666MHz etc. (the 9-9-9-27 2T common for 1600 is only the Primary timings, there's secondary and tertiary timings beyond those, over 30 usually, and it's in those 2 sets where most incompatibilities are found). XMP is just a preset profile reading those directly off the ram itself. For ddr4 this usually includes every setting below rated speed, so for 2666 you'll also find on the jadec table 2400, 2133 and 1866 but xmp #1 would be 2666