So i stuck a 7900x into my dark, put in 4 dimm's of g.skill that i had been using in another pc. Booted up the first time just fine, but I noticed in the bios that it was only showing 3 channels of ram as active. Its trident z ram, and the rgb lighting is working fine on all sticks, but for some reason, the motherboard is not recognizing anything from dimm slot 2. Its odd, i have a 7900x, the book says that if you are running a single stick with skylake-x to populate dimm slot 2 first. If I do that, I get a post error 55 for memory. If I take the same stick from dimm slot 2, and place it in dimm slot 4 (far right) boots up just fine. Ive tried all 4 sticks by themselves in dimm slot 4, to ensure they all work with the board, and every stick will boot by itself in dimm slot 4. I can have dimm 3 and 4 filled, boots and shows 16gb, and 2 channels. If I add 1,3,4 it shows 3 channels and 24gb, if i move them to 2,3,4, it shows up as 2 channels and 16gb. if i install dimms 1,2,3,4, it only shows up as using channel 1,2,3, and channel 0 is empty, and it shows I only have 28gb of ram running @ 2133. I can load xmp profile 1, and the ram boots with correct timing @ 3200 mhz
 
I haven't installed a os or anything yet. Once I noticed the memory issue I stopped there and tried to fix it. Anyone have any advice? Am I going to have to RMA this board? Ive tried every arangement of memory sticks. No stick works in slot 2, but every stick that wont work in slot 2, works perfectly fine in every other slot, so i know its not my ram.
 

have not updated bios yet

Power off and unplug the computer. Pull out the RAM and use a can of air to remove any debris in the RAM slots. Reinstall the RAM and test again.
 
Also, simply re-seating the RAM or even moving the sticks from one slot to another might show that a stick of RAM is bad.

GGTV-Jon

arestavo
Power off and unplug the computer. Pull out the RAM and use a can of air to remove any debris in the RAM slots. Reinstall the RAM and test again.
 
Also, simply re-seating the RAM or even moving the sticks from one slot to another might show that a stick of RAM is bad.

Making sure the ram slot is clear of any foreign material is a good suggestion - as to the rest go back and read the rest of the OP, as he has already confirmed which slot is acting up and no issues with the sticks themselves..

 
this.
 
every ram stick works fine, by themselves, with only 1 stick at a time, in dimm slot 4, each stick works and boots up, so each stick works individually. Each stick works in every dimm slot except dimm 2, and no memory stick works in dimm slot 2. ive also very closely inspected the dimm slot, blown it out, no debris or any apparent damage to connecting points.

lol i have no idea whats going on.
 

cpuz and windows/bios saying two different things?

all 4 lights are on


even if i remove a memory stick

I even removed memory sticks from slot 3 and 4, and the led lights stayed on, so im not sure they have anything to do with a memory being in the slot, and have more to do with the cpu and memory availability. i have a skylake-x processor, so all 4 dimm's should be available, if i had a kabylake-x processor, then only the two led's on the dimm's 3 and 4 would light up.
 
this light is red though, not sure what it means though

 
if its messed up, and i need to rma, no big deal, its just going to be a hassle since i fully installed my water loop before testing it.

Give it steady voltage, like 1.2v, unless it needs 1.35v or 1.4v as stated on the memory for the speed.
 
My X99 will show 60GB instead of 64 if I don't give it manual voltage for 2133 memory. Automatic probably doesn't give it enough at POST so it skips a DIMM. I set mine to 1.2v manual and it shows up as 64GB every single time.
 
What g.skill memory are you running? You need to set your bios to XMP and manually input the voltage at either 1.35 or 1.4, depending on the model and specs listed on the RAM.

1.35 is what the xmp profile sets voltage too. dimm 2 is lighting up red now. I reset cmos, booted to bios with default settings, dimm 2 was still lit red. reloaded xmp, booted into windows, dimm 2 was still red. After running for a few minutes the dimm switched to white. 
 
Did a full shut down. With power off dimm 2 shows up as white, hit the power button dimm 2 lights up red, windows will boot, with dimm 2 still red, and after a few minutes it switches white again.
 
After dinner ill switch around the memory sticks and see if they all boot with a red led on dimm 2

If you've already updated to the latest BIOS then it's probably time to start the RMA process.

Looks like the specific board problem to me.
 
Check carefully if there is anything bad on the affected slot (maybe some dirt/debri in the connector). 
Make sure your CPU waterblock nuts are not overtightened at any corner. Worth to remove waterblock and CPU, to make sure no bent pins in the socket.
Based on your debug steps, it's clear that board have good power to memory slot, it detects memory presence (hence 55 error and CPU-Z shows 4 DIMMs as it has no way of knowing if actual memory chips working or not other than reading SPD data), and DIMM LED are in "active mode". But because actual DDR4 interface to that channel failed to operate, CPU disabled affected memory channel, leaving you with only 3 DIMMs operating. You can try to rub CPU pads lightly with pencil eraser to make sure gold pads are clean and shiny. 
 
 
If DIMM slot, CPU socket pins are not bend/dirty and there was no water spills anywhere, then your option is to RMA the board for replacement. 

Well TiN hit the nail on the head. It was indeed worth removing the cpu, because underneath I found a bent cpu pin. The only thing I can think that happened it when I was first installing the cpu, in an attempt to be careful I was delicatly holding the cpu and dropped it onto the socket from maybe 1/2" away. I never imagined it would damage the pins, and I completely forgot about it. I had 1 bent pin, and I bent it back into position. Im not sure it worked, is it even worth putting my cpu back in and testing it? I really dont want to risk my 7900x.
 
What are my options now? Can I send the board in for repair? Would I need to purchase a new board, or is it possible to fix the pin's? I purchased the extended warranty when I got the board, but I'm sure it doesn't covers "stupid user" errors. 
 
 

Give it a try. If it doesn't work, send it to EVGA and have it repaired or replaced for a fee. There's not much else that you can do.

Checking the CPU and memory socket was good advice. You narrowed it down to that point and there is pretty much nothing else that could have been wrong except for the motherboard PCB traces (unlikely) or CPU memory controller (unlikely). Usually the issue is caused by bent CPU pins or extremely uneven or excessive CPU heatsink attachment pressure.

Watch these
 
https://youtu.be/1fkioojsxX8
 
https://youtu.be/NY5_kCDlCbQ
 
https://youtu.be/O10BEZHxYY0

gobstoppable
Maybe my bent pin wasnt the only issue

This.  Pins don't look bad.  Jumped conclusion:  pins possibly problem -> pin looks bent -> pin is DIMM2 problem.
If pin problem, either CPU or motherboard could cause.  Need another CPU or board to determine which.

Well i've done it now... I went out and bought a magnifying visor, and some tiny tweezers. I have now completely broken the pin off. sigh... Just sent evga customer service an email, I'm hoping they can repair my socket, but I've read mixed things on different threads. Some people get told by evga that they don't do repairs, and wont provide any assistance. Other people have had their sockets repaired by evga for a fee. I will gladly pay the fee, I just hope this motherboard isn't trash now. 

Socket replacement
https://youtu.be/ZVt6pjnUd2s
 
Looks like they are in Aurora, Colorado http://qubexdatarecovery.info/