Question A1 and A1 DIMM slots not working

AssassinNation

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Nov 17, 2013
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Hello, guys!
My build:
MoBo: Asus ROG Maximus Hero VIII
CPU: i7 6700k
RAM: 2 sets of "Corsair Vengeance LPX CMK16GX4M2A2133C13(2x8 GB in each set)" (so 4x 8GB ram sticks, 32 GB total)
GPU: Gigabyte AORUS Xtreme 1080 Ti
CPU Cooler: Corsair H110i Extreme 280"

PSU: Corsair HX850i platinum

Side-note: Out of the 4 RAM sticks I have, one was broken long ago and I never RMAd it, so my PC was running with 3 RAMs x8 GB (24 GB of ram) for 3 years, without any problems at all. Had those sticks placed in DIMM A2 + B2(as recommended for 2 sticks) + A1. I will say it again, I HAD NEVER HAD PROBLEMS WITH THIS setup for more than 2-3 years. 24gb of ram

STRAIGHT TO MY PROBLEM NOW:
I decided to clean up my PC and reapply thermal pastes recently.
Cleaned the PC, reapplied paste, put everything back and turned it on. Everything was fine for 10-15 minutes, then I got "Blue Screen of Death". Restarted the PC and BSOD happened again after 5 minutes.
It then happened another 2-3 times until I decided to check my RAMs.
Downloaded Memtest86, turned it on and selected a minimum of 8 passes.
During the first pass, I got 800+ CPU errors. So I thought that I, somehow, fucked something(maybe the socket pins, or tightening the screws too much) up when placing the CPU back.
I removed everything and reassembled again. Put only 1 RAM this time in slot B1, PC started on first try and seemed to work fine. Turned off, checked the other 2 rams in the same slot, worked like charm, so rams had no problems.
Then I started moving 1 RAM to different slots. B1 and B2 worked splendidly, while A1 and A2 wouldn't POST at all, the screen was remaining black forever.
When the RAM was in A1 DIMM, I would get the 49 debug code right after starting the PC, then after some debug code cycling, it would stop at 01 code, then switch to 03 right after that and in the end a cycle of 01/03 debug codes would start.
When the RAM was in A2 DIMM, I would get the CC debug code right after starting the PC, then after some debug code cycling, it would stop at 55 code.

After that, I tried placing 2 RAMs together.
ALL 3 RAMS were working when placed in different combinations in slot B1 and B2 simultaneously. When trying B1 + A1/A2 or B2 + A1/A2, it wouldn't post again. So, in the end, I decided to remove the CPU again and check if there were any bent pins in the CPU socket, cleaned everything AGAIN, put back the CPU cooler, placed it right in the center, hand-tightened 2 diagonally-placed screws first, so that the pressure was even on both sides. I blew the dust out of everything possible, with compressed air, even from the back side of the MoBo!

Right now my PC is running Memtest86 for 8 passes, with ram placed in B1 slot. It's already the 4th pass and 0 errors.
Still, I can't place any RAM in A1 and A2 slots to get back to my 24gb setup.

SUMMARY of ALL the things I have tried:
-Clearing Cmos.
-Flashing BIOS again.
-Under-tightening CPU cooler screws to the point that I almost could move it freely.
-Checking all of 3 RAM sticks individually and in groups, in every slot, with every combination.
-Removing all the peripherals(GPU, keyboard, mouse, etc..) except for RAMs
-Changing all the cables.
-Changing some of my BIOS settings(like turning on XMP, etc...)
-Running 1 ram with different BIOS settings(to check if I fucked the settings up or not)
-Running 3 rams with the default BIOS settings, etc...


Right now I don't even know what to think of, I have tried every possible solution on the net and nothing seems to work, whenever A1 and A2 slots are in play, system doesn't POST, hanging at black screen.
The system just doesn't work like it did for 2-3 years. Nothing seems to malfunction aside from these slots. If you think that my mobo is at fault now... How could it malfunction out of blue? There were no power outages in my home or anything alike.

I'm out of ideas right now, please help me, someone!
Sorry for this, somewhat messy, text and bad English, it's my 4th language
 
May 25, 2019
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I had a very comparable issue for one month with two RAM slots apparently dead ; I googled and found the issue : I checked the pin on my CPU socket with a loupe and one was not in the same direction than the others. I could "burst" it in the right direction with a small needle. Maybe it helps
 
Reactions: AssassinNation
A off-the-cuff guess is a soldered connection underneath the CPU socket was cracked all along. The pressure from the heatsink mounting screws clamping it all together helped it make contact but once you took pressure off (by removing the heat sink screws) it opened up and can't reconnect now. Or possibly the same underneath one of the DIMM sockets.
 
Reactions: twanmal

AssassinNation

Honorable
Nov 17, 2013
33
0
10,540
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A off-the-cuff guess is a soldered connection underneath the CPU socket was cracked all along. The pressure from the heatsink mounting screws clamping it all together helped it make contact but once you took pressure off (by removing the heat sink screws) it opened up and can't reconnect now. Or possibly the same underneath one of the DIMM sockets.
Replying to your question about A2 B2.
The only slots working now, are B1 and B2. In the past I was running the system by have the 3 rams in slots A2, B2, A1
 

AssassinNation

Honorable
Nov 17, 2013
33
0
10,540
1
A off-the-cuff guess is a soldered connection underneath the CPU socket was cracked all along. The pressure from the heatsink mounting screws clamping it all together helped it make contact but once you took pressure off (by removing the heat sink screws) it opened up and can't reconnect now. Or possibly the same underneath one of the DIMM sockets.
What can I do now? That’s my problem. Can you suggest anything
Also, can a PSU cable be at fault in any way? Could, for example, 1 pin out of 24 that was giving power to A1 and A2 slot, get broken and result in this problem? Or is my understanding of how that cable works wrong ?
 
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What can I do now? That’s my problem. Can you suggest anything
Assuming my guess is right or close to right...you could try to find someone with an SMT/hot air reflow solder rework station and willing to reflow the ball grid array solder joints underneath your CPU socket and/or memory sockets.

Failing that:
1: be content. It's always a choice.
2: in the sockets that do work put higher capacity DIMM's to get to necessary memory capacity
3: Buy a new motherboard. If you had to pay someone to repair it i'm sure you'd pay more, and probably still wind up replacing it if they're not really qualified at reflowing a 1100 (or so) contact UFP ball grid array.
 
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AssassinNation

Honorable
Nov 17, 2013
33
0
10,540
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Assuming my guess is right or close to right...you could try to find someone with an SMT solder rework station and willing to reflow the solder joints underneath your CPU socket and/or memory sockets.

Failing that:
1: be content. It's always a choice.
2: in the sockets that do work put higher capacity DIMM's to get to necessary memory capacity
3: Buy a new motherboard. If you had to pay someone to repair it i'm sure you'd pay more, and probably still wind up replacing it if they're not really qualified at reflowing a 1100 (or so) contact UFP ball grid array.
Also, can a PSU cable be at fault in any way? Could, for example, 1 pin out of 24 that was giving power to A1 and A2 slot, get broken and result in this problem? Or is my understanding of how that cable works wrong ?
 
Also, can a PSU cable be at fault in any way? Could, for example, 1 pin out of 24 that was giving power to A1 and A2 slot, get broken and result in this problem? Or is my understanding of how that cable works wrong ?
I'm not sure exactly how your motherboard works but there are multiple wires and pins on the 24pin cable that in parallel bring 12V current from the PSU to the motherboard. That 12V is typically distributed to several VRM's that provide power not only to the memory DIMM's but also to VRM's that create the voltage needed for the chipset, audio, LAN and other consumers. So if that were faulty you'd have more symptoms than just those sockets.

EDIT add: but since you mention it, there are usually two VRM circuits for memory. I imagine one could be used for each pair of DIMM's and therefore the VRM for that pair, assuming they are powered by the same VRM, could be defective. But that doesn't explain why you operated for some time and then suddenly it fails. And, the situation is the same: you have to find a qualified tech to troubleshoot and replace SMT parts. They are expensive, you'll probably pay out what a new motherboard would cost for him just to render a diagnosis.
 
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AssassinNation

Honorable
Nov 17, 2013
33
0
10,540
1
I'm not sure exactly how your motherboard works but there are multiple wires and pins on the 24pin cable that in parallel bring 12V current from the PSU to the motherboard. That 12V is typically distributed to several VRM's that provide power not only to the memory DIMM's but also to VRM's that create the voltage needed for the chipset, audio, LAN and other consumers. So if that were faulty you'd have more symptoms than just those sockets.

EDIT add: but since you mention it, there are usually two VRM circuits for memory. I imagine one could be used for each pair of DIMM's and therefore the VRM for that pair, assuming they are powered by the same VRM, could be defective. But that doesn't explain why you operated for some time and then suddenly it fails. And, the situation is the same: you have to find a qualified tech to troubleshoot and replace SMT parts. They are expensive, you'll probably pay out what a new motherboard would cost for him just to render a diagnosis.
Unfortunately there isn’t any qualified tech that could replace the SMR parts. So for now I’m content with just the B1 and B2 slots working. i turned on memtest with 2 rams installed, yesterday. Did 10 passes. Fortunately had 0 errors!!!
Will my performance be decreased now that i run 2 rams in the same channel(b1 and b2) ?
 
Unfortunately there isn’t any qualified tech that could replace the SMR parts. So for now I’m content with just the B1 and B2 slots working. i turned on memtest with 2 rams installed, yesterday. Did 10 passes. Fortunately had 0 errors!!!
Will my performance be decreased now that i run 2 rams in the same channel(b1 and b2) ?
You're no longer enjoying the benefits of dual channel operation. So yes, performance will decline.
 
I use my pc only for gaming. How big difference will it make for me?
As with most things computer, the answer is "it depends". GamersNexus did a test a few years back:

The money paragraph for your question is this:

"Gamers, mainstream users, and office users shouldn't care. Actually, at the end of the day, the same rule applies to everyone, simulation pro or not: It's density and frequency that matters, not channeling. Quad- and better channels theoretically have a more profound impact, but this is in-step with the increased density of kits that are targeted for quad-channel platforms. If you want to push speed, density and frequency should be at the top of your list. Generally, when you're spending that kind of money, you're going with a multi-channel kit of two or more anyway, but the point still stands. "

He wrote this in 2014, DDR3. But I have to think the same considerations apply today.

The whole article (and it's very detailed) is here:
https://www.gamersnexus.net/guides/1349-ram-how-dual-channel-works-vs-single-channel
 

AssassinNation

Honorable
Nov 17, 2013
33
0
10,540
1
As with most things computer, the answer is "it depends". GamersNexus did a test a few years back:

The money paragraph for your question is this:

"Gamers, mainstream users, and office users shouldn't care. Actually, at the end of the day, the same rule applies to everyone, simulation pro or not: It's density and frequency that matters, not channeling. Quad- and better channels theoretically have a more profound impact, but this is in-step with the increased density of kits that are targeted for quad-channel platforms. If you want to push speed, density and frequency should be at the top of your list. Generally, when you're spending that kind of money, you're going with a multi-channel kit of two or more anyway, but the point still stands. "

He wrote this in 2014, DDR3. But I have to think the same considerations apply today.

The whole article (and it's very detailed) is here:
https://www.gamersnexus.net/guides/1349-ram-how-dual-channel-works-vs-single-channel
Deeply appreciated!!! Thanks very much.
On a side note, I decided to setup my bios in a more “deeper” way. But as a newbie, I don’t know which settings and how I should alter them. I’m talking right now about CPU and RAM bios settings. I would be very thankful if you could help me up with it. In 3 years I of using this pc, I haven’t touched CPU and RAM settings. Can I pm you?
 

AssassinNation

Honorable
Nov 17, 2013
33
0
10,540
1
I had a very comparable issue for one month with two RAM slots apparently dead ; I googled and found the issue : I checked the pin on my CPU socket with a loupe and one was not in the same direction than the others. I could "burst" it in the right direction with a small needle. Maybe it helps
This was the reason all along. I fixed the pin and all slots are working again!!! Cheers to you!!!
 

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