gbaker3

mike406
Slots 1 and 3??? Unless you're a programmer and like to start counting at zero, you have your RAM inserted wrong. You need to populate slots 2 and 4 when running a dual channel memory kit. After this is done, enable your XMP profile and test again.
 

To be fair, populating slots 1 & 3 first makes logical sense if you don't read the manual. It's not like he used Slots 1 & 2, which if someone knew nothing about how dual channel ram works, they would probably try first.

bob16314
AIDA64 Extreme (trial or pay)..Go to Motherboard -> Chipset -> Memory Controller -> Active Mode and it will tell you what mode your RAM is running in..Same with CPU-Z -> Memory Tab -> Channel #.

Slots 1 and 3, and slots 2 and 4 are "Memory Banks"..The Intel chipset sets up the "Banks" to auto-run in Dual Channel Mode when populated as stated above in Post #3.

You can even have one 4GB stick and one 8GB stick populating one "Bank" and running in Dual Channel Mode, but only the lower/matching 4GB will do so, the upper/non-matching 4GB would run in Single Channel Mode..If you have three sticks in two different "Banks", only the matching RAM density in matching "Banks" will run in Dual Channel Mode at the lower/matching density while the lone stick will run in Single Channel Mode..That's by Intel chipset design, been that way.

According to the Z170 FTW manual, slots 1 and 3 are the primary priority slots and slots 2 and 4 are the secondary slots and it goes on to say that it is required to populate slot 1 first (which is typical), as opposed to the Z170 Classified K manual which says slots 2 and 4 are the primary channel and slots 1 and 3 are the secondary channel and it is required to populate slot 2 first and the board will not POST if slot 2 is not populated..Although the figures show differently and maybe incorrectly between the two boards, dunno.
 
If you have one "Bank" running in Dual Channel Mode and one "Bank" running in Single Channel Mode, software will report Dual Channel Mode because it's common sense that a lone stick in one "Bank" will only run in Single Channel Mode.

I would roll with slots 1 and 3 on the FTW board and see how it works..If not, then roll with slots 2 and 4.

Cordorb
1. Did the downloaded version get updated - I don't have my Z170 any more only a Z270 and Z370
 
2.  I think on my first day of building I before (reading manual/downloading manuals ) I used 1 and 2 slots  :-)
 

batboy88
Is there a specific reason why most it like 2 and 4 but a few are like 1 and 3...