[SOLVED] Aorus Z390 Master won't boot with 4 DIMMs occupied?

[fdjkaja]

Hi,

I recently built a PC and have an Aorus Z390 motherboard, i9-9900K and a kit of 16x4 Corsair Vengeance RGB PRO 3000mHz. The PC will boot when I use only 2 slots (1 and 3) but will not work when I use all 4. Instead, all the LEDs turn on, fans will spin, but my monitor won't react and I get the flashing error codes: CC, C2, C4, C5, 4C, 80. I tried clearing the CMOS, fiddling with the BIOS, and even updated it to the current version. Has anyone else had a similar problem or know how to fix this issue? Thank you.

 

[Darkbreeze]

Did the memory ALL come together in one FACTORY kit, or was it two separate kits of the same model number (Or even different model numbers with similar specs)?

You may need to go into the bios with only two sticks installed and bump up the DRAM voltage a bit. Start with .005v, save settings, exit, shut down, install the other two sticks, power on, see if it will POST. If not, two sticks back out, back into the bios, increase the DRAM voltage by another .005v, rinse and repeat.

All these steps are covered here:

*Resolving memory problems and setting up XMP/DOCP/AMP profiles

Are they not working together with all sticks installed at the DEFAULT speed and timings, or not working together with XMP enabled at the ADVERTISED speed?

 

[fdjkaja]

Did the memory ALL come together in one FACTORY kit, or was it two separate kits of the same model number (Or even different model numbers with similar specs)?

You may need to go into the bios with only two sticks installed and bump up the DRAM voltage a bit. Start with .005v, save settings, exit, shut down, install the other two sticks, power on, see if it will POST. If not, two sticks back out, back into the bios, increase the DRAM voltage by another .005v, rinse and repeat.

All these steps are covered here:

*Resolving memory problems and setting up XMP/DOCP/AMP profiles

Are they not working together with all sticks installed at the DEFAULT speed and timings, or not working together with XMP enabled at the ADVERTISED speed?

Thanks for the reply. I'll read that page now.

At first, I had 2 32GB kits of the exact same model of memory (pcpartpicker didn't advise me against this, excuse my foolishness, i'm new), and when that didn't work, it seemed to me that there must have been some minute differences between them that caused the problems, so I returned those and instead purchased a single 64GB kit.

The problems persisted, however, even using a single kit. I've reset the CMOS both with the switch, and manually by removing the battery. The memory is running at the default speeds, because any options to modify the speed, voltage, or timing are greyed out in BIOS and I can't seem to figure out how to change this even after consulting the manual.

What's odd to me is that all the modules work, but only in slots 1&3. I've tried putting 2 modules into slots 2&4 and leaving 1&3 empty (Yes, this seems to be allowed according to the manual) and it simply will not boot, which led me to believe that the actual DIMM slots 2&4 on the motherboard are defective something -- but the LEDs on the RAM still illuminate, even in the "defective" slots, which kind of contradicts that theory.

Update: Thanks to the info you provided, upon some experimentation the computer is now booting with slots 1, 3, and 4 occupied. All 48GB of ram are recognized. It is just the 2nd slot that refuses to cooperate. I'm really lost at this point and I'm thinking it must be an issue with the board.

 

[Darkbreeze]

What is the EXACT model number of your motherboard?

WHAT, exactly, did you change that allowed you to boot with a third stick installed?

 

[fdjkaja]

What is the EXACT model number of your motherboard?

WHAT, exactly, did you change that allowed you to boot with a third stick installed?

It's the Z390 AORUS MASTER (yeah that's the actual model number oddly)

And as far as changes that allowed me to add another stick, none. I've changed nothing in BIOS and I've not removed or added any hardware to the build. I figured at first there's no way it would boot with a module in the 2nd B channel (#4) if there wasn't another in the 2nd A channel (#2) but, I figured it's worth a try and it did work.

 

[Darkbreeze]

When two sticks only are used on that board they should be installed in the A2 and B2 slots. If the system will not post with them installed in those slots then there is a problem with motherboard and you should return it or RMA it.

Try installing two modules in the A2 and B2 slots, with the power off and the PSU unplugged from the wall. Then remove the CMOS battery for five minutes, during that five minutes press the case power button for 30 seconds. Then reinstall the CMOS battery, restore power to the power supply, power on and see if it will POST. If it will not, try replacing one of the modules with either of the other two modules. If it still doesn't work, try replacing the other module with any of the other two modules not currently installed.

That should eliminate it being one stick of memory. If it still doesn't work, then there is a problem with the motherboard and should be returned or warrantied.