https://www.asus.com/Motherboards/ROG-MAXIMUS-VIII-HERO-ALPHA/HelpDesk_QVL/
http://dlcdnet.asus.com/pub/ASUS/mb/LGA1151/MAXIMUS_VIII_HERO/4L-DRAM_QVL_table-0615.pdf
http://dlcdnet.asus.com/pub/ASUS/mb..._HERO_ALPHA/M8HA_One_Page_Full_QVL-112315.pdf
3200:
4x4:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233797 $175
4x8:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820236037 $166
is that right? 32GB for less than the price of 16GB? Something's got to be wrong here...
64GB: GSkill, F4-3200C16Q-64GRK,
http://www.newegg.com/Product/Product.aspx?Item=N82E16820232329 $360
That sounds more reasonable.
2133:
64GB:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233733 $270
32GB:
http://www.newegg.com/Product/Produ...escription=CMK32GX4M4A2133C13&N=-1&isNodeId=1 $136
As you can see from their Certified list, the first time you can go with a 64GB kit is at DDR4 3400 (starting from the fastest down).
F4-3400C16Q-64GVK $429
F4-3400C16Q-64GTZ $449
So figure 4x8 kit would be half that price.
There is a discernible difference paying $430 for 64GB of 3400 and $360 for 64Gb of 3200. But when you install 4 sticks of Double Sided RAM you may not get the full speed reporting in OSX. So you may want to go with 3400 memory just to get real 3200 speeds.
You have to decide what your price point is, how much you are willing to spend. I usually suggest whatever the price of the CPU you paid. So if you have a $350 CPU then paying around $350 would be reasonable. If you have a $230 CPU then paying around $230 - $250 would be reasonable. What you don't want to do is to install 4x4 now and in a year decide that you should've gone with 4x8 or 4x16 - because then you will need to either sell the old RAM or just throw it in the drawer.
So, let's say that you want DDR4 2400 memory, just to be on the safe side. Uh, they don't sell 16GB sticks for that board.... So you'll need to go to 2666 speed. F4-2666C16Q2-64GRB will cost $300. Now you have to decide if you would rather pay $300 for 2666 or $360 for 3200. One difference will be that 2666 runs at 1.2V and the 3200 runs at 1.35V. If you have a lesser quality PSU you may want to stick with the 2666, and if you have a superior PSU then you may want to stick with the 3200. Hopefully the mobo has better voltage regulation and filtering than cheaper boards.
Me, I tend to think that fans over RAM sticks is a little gimmicky. Well, that and the fans are bound to interfere with cpu air coolers, but I guess they would be the way to go if one is going CPU water cooling. But why could they need to be cooled, unless one is overclocking the RAM?, and if one is going to overclock the RAM why not just go with a higher speed stick? (Probably because they are not made in that size or they are overly expensive, like DDR4 4200 @$500 for 16GB).
Still I wonder what "When running XMP at DDR4 3200 MHz or higher, the system’s stability depends on the CPU’s capabilities" means?
One of things you want to pay attention to is the RAM voltage. Stock 2133 will probably be running at 1.2V and 3000 and above will be running at 1.35V. So make sure that you have a really good PSU that can supply 1.35V of very clean power. You have to research whether the mobo you're thinking of buying (any mobo) has memory voltage problems because some have been reporting as throttling the voltages too high even when 0.1V increments are selected (typically going up 0.5V instead of 0.1V when setting in the BIOS).
