[SOLVED] Specific RAM Channel not booting

[Ljac95]

I recently upgraded my CPU from an i5 6600k to an i7 6700k, at the time of my upgrade my RAM was in Dual channel configuration (DIMMs 2 and 4 as recommended in the manual). The motherboard is a MSI Tomahawk Z170A, when I went to boot the PC back up it wouldn't post and was showing an error LED for DRAM. After trying several configurations I realised the PC would only post if there was a stick occupying either DIMMs 1 and 3, as a result I can run it in Dual channel configuration using the opposite channel to the one recommended to be used first.

When I tried booting in a single channel configuration it would post and detect the ram in the slots but it won't post in dual channel for DIMMs 2 and 4. The PC works fine with other channel except for the fact that I have encountered instability using the XMP profile (which i'm assuming is why they tell you to use channel A first). I have tried updating the BIOS with no impact, I would like to us the other channel simply because it means I am forced to keep my RAM at 2133mhz as opposed to 2400mhz.

Apologies if this isn't very clear and please let me know if you need further details or anything clarified. Any advise or suggestions as to what is causing this an potential solutions will be much appreciated.

Thanks

 

[DavidM012]

https://forum-en.msi.com/index.php?topic=259589.0

bent pins in cpu socket

 

[Ljac95]

https://forum-en.msi.com/index.php?topic=259589.0

bent pins in cpu socket

 

[Ljac95]

ok thanks, I had a fear it could be that. I did check initially at the time but will give it another look.

 

[Ljac95]

https://forum-en.msi.com/index.php?topic=259589.0

bent pins in cpu socket

https://forum-en.msi.com/index.php?topic=259589.0

bent pins in cpu socket

 

[Ljac95]

So I took out the motherboard, removed the cpu and spent a good while with a magnifying glass going over the whole socket but for the life of me can't see any bent pins. I reassembled everything and cleared the CMOS for good measure and still nothing on RAM channel A, I don't suppose there's anything else that could cause this?

 

[DavidM012]

bent pins in dimm socket? It seems reasonable that since you switched a cpu something could've happened to the pins in the socket. It could be slight and nearly imperceptible. How could it be a problem with the memory compatibility if the dimms were working fine with the 6600k? You can try checking if the memory is on the qvl if it is then that only isolates the problem more to the cpu socket.

It has also been suggested that the heatsink being ever so slightly unevenly seated might push the pins out of alignment so you can try to ensure that it's even buy tightening the opposite corners half a turn at a time.

Otherwise baffled. Can it be that two nearly identical cpu's won't run the same memory overclocked? I suppose the memory could be qvl with the i5 but non qvl with the i7.

 

[Ljac95]

The DIMM slots in question are far enough away from the heat sink that I doubt it would come into play, just to clarify what does "qvl" refer to (apologies i'm fairly new to PC troubleshooting). If it helps at all the exact issue I have experienced when running the XMP profile on Channel B is the PC locking up with a buzzing noise coming from the speakers.

 

[Calvin7]

Looks like you have not identified the memory you are using.

I suggest listing it by part number or link to it.

 

[DavidM012]

qualified vendor list. The motherboard manufacturer publishes a list of memory by part number that has been tested with the board and cpu. There is a list for each cpu combined with various dimms.

PC not booting could be a symptom of non qvl or incompatible memory. So it's qvl for i5 6600k but non qvl for the i7 6700k.

But also since you've been moving the cpu's and dimms around a socket problem with either could also be a factor. You could try cleaning the dimms contacts with isopropyl alcohol, make sure it's all dry when re-seat.

Can also put the old cpu back to see if it still works in original config. then compatibility is more certainly the problem.

 

[mgallo848]

You may just need to update the BIOS.

Some versions of the 6600k AND the 6700k need BIOS 1.9. while other versions of the same CPU's can run on ver 1.0

https://www.msi.com/Motherboard/support/Z170A-TOMAHAWK#support-cpu

 

[Ljac95]

I had already updated the BIOS to version 1.9, however I think you may have cracked it with the qualified vendor list. The RAM I am currently using is Corsair Vengeance LPX DDR4 2x6GB and the part number is CMK16GX4M2A2400C16 however, the closest thing I could find on the compatibility menu is CMK16GX4M4A2400C14. Based on this do you think the RAM may be simply incompatible which is why there are so many weird issues? Also would you say at this point the best solution is to get some more ram that is compatible?

 

[mgallo848]

It's possible but it's hard to say. I would try going back into the BIOS and enable XMP mode and give that a try

 

[Ljac95]

I've tried enabling XMP and that's what is triggering the instability + it won't boot in Channel A only Channel B.

 

[DavidM012]

If you ask me I'd check qvl + review with your mobo to see if anyone's successfully overclocked, might be tough to find a review with the combo you're looking for though. for a shot in the dark I'd pick a qvl module first. There might be a limited range of useful modules for your board and less reviews in which case you can only take the chance, you could ask other 6700k owners if they have a tomahawk and what mem they used, it's a lot of searching and digging but who knows, maybe you'll find a great deal on some ram.

 

[Ljac95]

Thanks for the advice, I'll try a qvl module a let you know if it works. I did try having a look on around but struggled to find anything that specifically would help.

 

[Ljac95]

Just thought i'd give an update, tried 2 new sticks of RAM in the same configuration (2x8) albeit at a higher speed (3000mhz). After installation I was able to boot successfully in the RAM slots that were previously not working. In addition I have so far been able to run in XMP with no issues (touch wood). Thanks for all the help and suggestions.