Question PC won't post if mixing two brands ECC RAM with diff ranks

[giffmetango]

Mobo : X99 Nuvoton NCT6779
CPU : 2697v3

I can only make the PC boot if remove other
4 Slot ram
1-3 micron, 2-4 hynix not working
1 micron,2-4 hynix not working

1-2 or 2-4 or 3-4 hynix/micron(same brand and rank is working 2RX8 or 4RX4)

So i need to find other hynix 4RX4 32x2 to replace micron for it to work right ?

Currently i just removed 16x2 set and use 32x2 set instead, it working perfectly, i thought mobo can easily mix between ram set/brands,mhz, but i'm wrong

it also related with ranking

 

[Lutfij]

So i need to find other hynix 4RX4 32x2 to replace micron for it to work right ?
+
Currently i just removed 16x2 set and use 32x2 set instead, it working perfectly, i thought mobo can easily mix between ram set/brands,mhz, but i'm wrong
You should use identical sticks of ram, in fact you're advised to invest in a ram kit which comes matched from the factory after binning.

Mixing and matching ram sticks is always hit or miss. In your case, it's a miss and you'll see the same trend across the past decade on our forums

 

[giffmetango]

So i need to find other hynix 4RX4 32x2 to replace micron for it to work right ?
+
Currently i just removed 16x2 set and use 32x2 set instead, it working perfectly, i thought mobo can easily mix between ram set/brands,mhz, but i'm wrong
You should use identical sticks of ram, in fact you're advised to invest in a ram kit which comes matched from the factory after binning.

Mixing and matching ram sticks is always hit or miss. In your case, it's a miss and you'll see the same trend across the past decade on our forums

yeah, normally it should be 4x 16GB but 32GB is same price as 16GB so i pick 32GB instead without knowing it's 4rx4 instead 2rx8 may causes many problems

 

[bill001g]

Welcome to the massive trap of trying to upgrade memory. Memory is extremely sensitive to everything it seems. You look a the path the copper traces take on a motherboard or other device and they go to a lot of trouble to make sure these are exactly the same length. Seems even 1mm difference in length between the traces to different pins on a memory module makes a huge difference.

There appears to be very large difference between individual memory chips even when they are manufactured on the same silicon wafer. Watch some of the youtube video that show tours of memory manufacturing plants. The machines that build the actual modules test all the actual memory chips before they are put on a board trying to find closely matched groups. They then test the different modules to ensure that when you use multiple modules they work together at the rated speeds.

For us end users we do not have a unlimited bin of parts we can try combinations of to see which will work together. We are stuck either buying what is factory tested to work on our motherboard or you play the memory slot machine and hope to get units that will function together.

This is still only part of the issue you still have both the motherboard and cpu chips themselves that may or may not work with particular sets of memory.

When you do anything that is not listed on the QVL list of memory configurations you are stuck testing everything yourself. There are massive number of setting for all the different timing and voltages you can play with. With enough time you might find some combination that will function.