Asus Z170-AR: bad DIMM slot?

[beatle]

Picked up an Asus Z170-AR, i5-6600K, and two 8GB sticks of Crucial DDR4 this weekend. Put it all together and it would not post. Checked the red light on the board which indicated an issue with RAM. Hit the "MemOK!" button as advised in the motherboard to let it sort out the timing - still would not post.

Tried pulling a stick out of the second slot and it fired up as normal. Ok, so maybe it's a bad memory stick. Swapped the good stick out for the suspect one, all systems go. Ok, any time I have a stick in the fourth slot (B2) it will not post.

Before I pull the board and take it back to Microcenter for another one, is there anything else I should try?

 

[lehtv]

Does it work with modules in A1 and B1?

 

[beatle]

I forgot to mention that I actually tried A1 and B1 thinking they were the defaults. When I looked at the manual, it actually calls out A2 and B2 as the slots to use when installing two DIMMS. When I had the sticks in A1 and B1 the board did not post.

 

[lehtv]

As far as I can tell, here's what you've figured out:
- A1 & B1 does not work
- A2 & B2 does not work
- neither module will work in B2 with other slots unused
- both modules will work in A2 with other slots unused

Does it work with a single module in A1? What about B1?

It seems that the modules themselves aren't faulty. But if you bought separate 8GB modules instead of a 2x8GB kit, it's possible they are not compatible with each other and therefore refuse to work with both installed.

It's also possible that the RAM you're using just isn't compatible with the motherboard. However, this is very unlikely if the memory was bought in a kit and if the memory is listed in the motherboard's memory QVL.

The final possibility is that the motherboard is faulty. You might think so based on the fact that a single module in B2 doesn't work while a single module in A2 does. But this could also be explained by the RAM not being compatible. Or perhaps a single module B2 isn't meant to work in the first place - perhaps you're supposed to have either one module in A2 or two in A2 & B2. Also it would be easy to prove/disprove whether the motherboard is faulty by trying a kit that's listed in the motherboard memory QVL, assuming your RAM isn't.

 

[beatle]

Yes, that's a good summary.

The modules were bought as a 16GB (2x8GB) kit. A couple of Crucial Ballistix model numbers (which are what I have) are listed under the QVL, but it was late last night and I didn't see if they were the specific modules I bought.

The manual specifies the installation for various number of modules:

1 module: A2
2 modules: A2 + B2
4 modules: A1 + A2 + B1 + B2

I'll double check the QVL against the modules I have. If they're on the list, I think I've exhausted the possibilities.

 

[beatle]

Figure I'd tie up the loose ends here.

I replaced both the board and the RAM with the same components. Same issue. Taking the RAM back to Microcenter, I tried some Corsair LPX DDR4-2400 but had the same results. At that point I just start trying different combinations of slots, finally posting and working successfully with both sticks in A1 + A2. Not sure if the other two slots work properly as I only have two sticks at the moment, but at least it's working.

Not sure if this qualifies as "dual channel" since I have both sticks in the first channel. Or am I off base with how channels are defined nowadays?

 

[beatle]

Funny how Google works. I just found this thread when searching for solutions to my "new" problem. I picked up another 16GB kit of Corsair LPX - same model as before. I popped in the two extra sticks and the machine refused to post. I'm guessing I have one or more bad DIMM slots. Since I picked up the warranty on this board, I think I'm going to abandon the Z170-AR as a platform and go with something else.

 

[dichthuatchaua]

Not sure if this qualifies as "dual channel" since I have both sticks in the first channel. Or am I off base with how channels are defined nowadays?

 

[ch33zw1z]

Funny how Google works. I just found this thread when searching for solutions to my "new" problem. I picked up another 16GB kit of Corsair LPX - same model as before. I popped in the two extra sticks and the machine refused to post. I'm guessing I have one or more bad DIMM slots. Since I picked up the warranty on this board, I think I'm going to abandon the Z170-AR as a platform and go with something else.

I have the same board. It's very finicky with ram configs. Asus is still releasing uefi updates on a bimonthly basis, only citing system stability as the fix.