Update:

This post details what this person used to have 96 GB RAM on his Alienware M18:

https://www.reddit.com/r/Alienware/comments/145dpv4/m18_running_96gb_ram/?rdt=53976

From what i understand 64 can run but at lower speeds. i have 32gbs running at 5600 so 64 i think is 5200 but dont quote me 

@Sydneyblue​ 

Hi and Thank you,

It could be but check this out from Reddit:

I just swapped the 4800MHz 64GB (2X32GB Kit) in my M18R1 with the Crucial 96GB (2X48GB Kit) (https://www.amazon.com/Crucial-2x48GB-5600MT-5200MT-CT2K48G56C46S5/dp/B0C79K5VGZ). I realize Dell said max supported was 64GB, but figured that was all that was available and tested at the time, so thought I would give it a try. No BIOS changes necessary. The laptop took a couple minutes to think about it (RGB keyboard usual light show) before anything showed up on the screen, and then voila, the laptop booted and I am now seeing 96GB of RAM available at 5200GHz. I run ML models and am training full out for a couple hours now and no issues.

@Stefos4​ Hi, I'm planning to upgrade my Ram from 32gb 5600 that came stock with my M18 R2.
I want to upgrade because I got a good deal for the laptop and have some money saved up right now I can spend and make it future proof. Will be using it for gaming purposes only.

So 64 gb 32x2 at 5200 or 96gb 48x2? Will it work at 5200? or will it downgrade the clock speed?

@Axat​ 

Hi Axat,

I ordered the 2 96GB Crucial RAM kits mentioned in the Reddit post.

I will install them either this week or early next into my Alienware M18 R1 and M18 R2.

I'll run CPU Z and update my post here.

Currently I run 64 GB of RAM at 4600.

Stefos

@Axat​ 

Get some Crucial DDR5 5600 (2x32) it will run at 5600MT

You can also get Mushkin Enhanced Redline 96GB (2 x 48GB) DDR5 5600  It will also run @ 5600MT

My M18 R2 came with 64GB PC5600 no issues with good ram

And you can run DDR5 6400 SODIMM too.

@sonofthemosthig​ 

Thank you sir

I appreciate it....I just ordered the Crucial CT64G56C46S5 64GB RAM sticks for each Alienware M18 I have.

I hope that if I have a slower RAM stick, that the machine will boost the speed up to 5600 or 5200 altogether.

Stefos

@Stefos4​ Hi, I'm in a similar situation and also looking at this RAM for my M18. Were you able to get it installed and running? How is it so far?

Matt

@Cheezio​ 

Hi, Yes......great news:

the Crucial CT64G56C46S5 64GB RAM sticks work on the M18 R1 & R2 actually but

anything beyond 64 GB make the RAM run at 5200 mhz which IS stable. :)

No issues with either M18 R1 or R2 with the current BIOS too.

Stefos

@Stefos4​ 

Thank you for the memory ram upgrade information. I just purchased the same Crucial 96gb 5600 memory ram for $165 on Amazon. I have an Alienware M18 R2 and worked flawlessly. No bios or anything to setup. This whole time I was waitng on installing the max recommended. Which was 64gb and can not believed the 96gb work like a charm.