Which modules to add RAM to an existing Asus X99 2133?

[fabiospark]

Hello, I need to add some RAM to an ASUS X99-A with an Intel I7 of some years ago.
The RAM already installed is 16GB made with 4x4GB modules of F4-2133C15-4GRB.
Would it be safe to add at least 2x8GB modules of F4-2133C15-16GIS?
Thank you.
f.

[GSKILL TECH]

It is not recommended to mix separate memory kits / modules. Ideally a single kit should be used, such as:


https://www.newegg.com/g-skill-aegis...SoldByNewegg=1

[fabiospark]

Thanks for the reply.

Isn't the higher speed a problem? IIRC the Asus X99-A lists 2133 as its max ram speed.

But bear in mind that I don't know what I'm talking about, frankly...

[fabiospark]

I had the chance of trying 2x 8GB 2133 GIS modules.

Following Asus indications I put the two 8GBs into slots B2 and D2 while still having the 4GB ones into slots A1, B1, C1 and D1.

Then in the BIOS I could only see the first of the four 4GB modules in slot A1 and nothing else. I can't exclude bad placement of the modules in the sockets
as the PC in on the flor and the four socket on the left are almost hidden behind the pump and the fan of a cooling system with liquid.

I will make another try to see if anything change. Do I have to change any setting in the BIOS after I put in the new modules?
Thank you.

PS.
Before putting the 8GB in, I could see only three of the four 4GB modules in the BIOS but, after putting in and then out the 8GBs, now I can see all four 4GBs.

I'm still on an old bios because I've always been afraid to brick the PC: can an update help?

[emissary42]

Mixing different types of modules can lead to a wide range issues and only a few of them might be resolved with a BIOS update. Especially modules of different density can require different resistances and training parameters in general. The system dropping slots and/or channels during POST is the typical result.

To update the BIOS, make sure to either use USB flashback (if available) or a memory setup, that you have confirmed to work without issues.

If it does not work out, replace the existing memory with a proper quad kit, ideally one from the configurator link above.