Question Noob desperately needs help with trouble shooting new build

May 21, 2019
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Hello,
My build: CPU I7 8700k.
Cooler: Kraken X62.
MOBO ASUS Z370 PRIME-A.
2x8GB Corsair 3000 DDR LED PRO CL15.
SSD SAMSUNG 970 EVO 1TB
GPU RTX 2080 FE
PSU EVGA G3 1000W GOLD

Problems:
Memtest86 did all 4 passes. 2 errors showed up on Test 6 but only on the 2nd pass. View: https://imgur.com/lSdT2El


I am running XMP profile. Advertised timings, 3000 with 1.35V. VCSAA 1.2V VCCCIO 1.2V. Everything else is on Auto. Is it possibly a MemTest's bug ? I can MemTest again with a diffrent pair of Ram but right now I doubt it's the ram (explained further below). NEWEST BIOS available.
------Running realbench 2.43 stress test at the momment. No error for 3 hours so far. Will let you guys updated until its 8th hour and then move to Prime95 test
Now here lies the main problem. As you might know I have 4 RAM slots. From left most or closest to CPU, B1;B2;A1;A2. System Won't boot and the light on motherboard stucks at DRAM when I install any single DIMM of RAM on slot A1, A2. B1 and B2 boot just fine. As the manual said, if I want to run dual chanel then I will be using B2 and A2. Well, I tried to run dual chanel from any kind of combibination and system ONLY boots if I run dual chanel on slot B1 and B2. Would this hinder my performance when the recommaned slots are B2 and A2 ? I also tried another pair of RAM and the same problem persisted which led me to think that the problem is my motherboard rather than my rams. Are my ram slots defective ? should I RMA my motherboard ? I have read some of the reviews on Amazon and a lot of people have problem with this crap motherboard. What a pain in the rear to pull everything out !
 
if you put memory in B1 and B2, I am not sure that you are using dual channel and, yes, not using dual channel will reduce memory performance ... 10% ish, if I recall correctly.

So, 3000 is technically an overclock of the memory controller. The thing is that it works fine 99% of the time. I would be tempted to drop down to stock speeds (2666) and retest. If you have an issue at 2666 then I would suspect a flaw in the MB, memory, or the CPU (remember that the memory controller is on the CPU). If no flaw is detected at 2666, but you see issues at 3000 then there might an issue with the memory controller, but it is also possible there is an issue with the RAM (but less likely since you tried different pairs).

If things work at 2666, but not 3000 should you RMA. Tough question. RMA is always a pain and the performance boost is pretty small. The ASUS Prime boards are not crap ... but those does not mean you don't see a dud from time to time.
 
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May 21, 2019
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if you put memory in B1 and B2, I am not sure that you are using dual channel and, yes, not using dual channel will reduce memory performance ... 10% ish, if I recall correctly.

So, 3000 is technically an overclock of the memory controller. The thing is that it works fine 99% of the time. I would be tempted to drop down to stock speeds (2666) and retest. If you have an issue at 2666 then I would suspect a flaw in the MB, memory, or the CPU (remember that the memory controller is on the CPU). If no flaw is detected at 2666, but you see issues at 3000 then there might an issue with the memory controller, but it is also possible there is an issue with the RAM (but less likely since you tried different pairs).

If things work at 2666, but not 3000 should you RMA. Tough question. RMA is always a pain and the performance boost is pretty small. The ASUS Prime boards are not crap ... but those does not mean you don't see a dud from time to time.

Thanks for your reply. I am not running dual cahnnel even if system detects total of 16Gb of RAM ? lets me drop it back to 2666 and retest. Isn't stock speed 2133 ? should i change timings to auto, too? Right now the suspect is the motherboard because 2 of 4 slots don't work.
 
May 21, 2019
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You have an ASUS MOBO. If you are running two sticks, they need to be in B2 & A2 B2 is the slot closet to the outside of the motherboard on the right, A2 would be the 3rd slot. The 4th slot is the closest to the Processor / Socket. B1 & A1 is the other channel.
Yes, understood. I am fully aware that default slots for dual channel are B2 & A2. The Problem is system wont boot with dual channel in B2 & A2. It only boots with 1 Ram stick in either B1 or B2 or 2 ram sticks in B1 and B2
 
You have 16 GB of RAM (2x8GB) if you are in single channel or dual. Dual channel just gives you more performance. Think of it like this ... imagine you can read two books at once. I give you 2 setups; one is a single book that is 16 pages ... the other is 2 books that are 8 pages. The same amount of information in both setups. Clearly you could read the two books twice as fast as the single since you are reading them simultaneously. Naturally it does not work out quite like that in the real world, but there is a boost to using dual channel.

And yes ... a bad slot is a possibility.
 
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May 21, 2019
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Okay. First thing that comes to mind is a bad DIMM slot. Those can't be fixed. I had that issue and had to buy a new MOBO.
Thanks for your reply. I am gonna change the speed of the RAM back to 2133 and everything else at default or auto. Do another Memtest and maybe use another pair of Ram to test to see if the problem is persisted.
 
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OK so 4 hours and RealBench does't crash nor any error (this was with everything stock/default/Auto except for XMP enabled).
BUT
I was in Bios trying to change the RAM speed down to 2133 and the screen went black. Fans and everything is still running. No POST light. Restarted the the PC and changed RAM to 2133. 5 minutes into MemTest, PC blacks out again but lights and fans are still on.
 
Since you have had a number of memory issues already, I would be tempted to suspect that is where the issue is. What you don't know is if it is an issue with MB, the CPU, or the RAM. What happens if you run it with one stick? If it crashes, then the other in a different slot.