DDR4 Quad Channel help needed

[bigcooljesus]

Hey guys,

I just put together a build with the new Haswell-E CPU's, 4 sticks of 4GB DDR4 RAM, and an Asus X-99A mobo that has 8 DIMM slots.

Here is a picture of the DIMM configuration for the X-99A mobo:

When I first assembled the system I had the four 4GB sticks in slots A1, B1, C1, and D1 as the manual recommends running perfectly fine but today I installed a new CPU cooler and after the install the C1 slot no longer works so only 12GB of the 16GB installed shows up. I tried using slots A2, B2, C2, and D2 but the system won't boot with that configuration. I then tried A1, A2, B1, and B2 (all four slots on the left side of the CPU) and voila! all 16GB show up again and are running fine!

Is there any performance difference (benchmark, I know real world is not going to be affected) between using the configuration I am now (A1, A2, B1, B2) vs. using the configuration suggested in the manual (A1, B1, C1, D1)? Am I still getting full quad channel "performance" or do the slots have to be used in a certain order (per the manual) to achieve this?

Thanks!

 

[Darkbreeze]

Run CPU-Z and look on the SPD tab. It should tell you if it's running in dual channel, triple channel, quad channel, or not.

 

[Eximo]

Either your cooler was interfering with the ram itself and causing it to not make a connection, or you had/have tightened the cooler down too tightly.

There will be no performance difference if the memory is in either slot set.

 

[bigcooljesus]

Run CPU-Z and look on the SPD tab. It should tell you if it's running in dual channel or not.

CPU-Z says "Quad Channel" so I guess that answers that.
Thanks!

 

[bigcooljesus]

Either your cooler was interfering with the ram itself and causing it to not make a connection, or you had/have tightened the cooler down too tightly.

There will be no performance difference if the memory is in either slot set.

I installed a Corsair H100i and tightened the screws as far as they were intended to go (hand tighten only). I did put a little more pressure than I normally would pushing down on the block while I was getting the screws lined up to keep it from sliding (since the pre-installed hoses tend to pull it in an odd if not held down).

If it was from extra pressure that the other slots are not properly working, what specifically could have caused this? Is it fixable?

 

[Darkbreeze]

Run CPU-Z and look on the SPD tab. It should tell you if it's running in dual channel or not.

CPU-Z says "Quad Channel" so I guess that answers that.
Thanks!

No problem. You should be fine. Take care.

 

[Eximo]

Usually one of the CPU pins will not be making proper contact or the RAM slot will be under stress and not quite touching all the pins when the memory is installed.

It comes up from time to time, just loosen the heatsink a little bit. But you have it working, so I wouldn't worry about unless you are planning to populate the remaining memory slots.