I’m a big fan of my Synology NAS, however one thing that irked me originally is that despite paying over £300 for my DS220+, I only got 2 GB of RAM. What? It’s 2023, and 2 GB is nothing. What gives? I then learned that you can expand the RAM on your NAS, by buying a new RAM stick.

But then I saw the price of Synology’s RAM, and I had another “what gives?” reaction! So this raises a few questions: why is Synology’s RAM so expensive? And can’t you just buy some random RAM, and stick this into your NAS? I wanted to answer these questions and more in today’s article.

Spoiler Alert: I recently purchased a ‘compatible’ Crucial 4GB RAM stick for £16…

Expandable Synology RAM: An Overview

A 4GB RAM module from Synology which is compatible with my current Synology NAS

Synology’s NASes are just like any other computer. They all have a motherboard, CPU, RAM and – of course – slots for expansion drives, which is where all your files are stored. Getting your NAS set up is often simple, and with minimal effort you will have a shiny new gadget to use.

A Synology NAS doesn’t just store files, though. You can use them as a surveillance station, run code on them, use it as a picture or audio hub, or even install a Docker VM and run… pretty much anything. Docker rules.

But all these fancy features requires RAM: lots of RAM. Unless you run the barebones Synology NAS and only one or two other applications, you will probably max out 2 GB of RAM fairly quickly. Your NAS will then feel slow: the admin console will be laggy, and file transfer speeds might even drop.

Thankully Synology has a solution: expandable RAM slots. If you look up the specification sheet for your intended NAS on Synology’s website, you will see that most of their NASes allow you to add more RAM:

The Synology website confirming that my DS220 plus supports expanded RAM modules

Note: Not all of Synology’s NAS devices allow expanded RAM. Some ship with the basic RAM module, and do not allow you to swap it out or add new RAM. Pretty much all of Synology’s more expensive NASes do support this, while some of their budget ones do not allow expanded RAM. But you should refer back to the product spec sheet if you are unsure.

While it’s good that Synology offer this, there is a key point from their website:

Please select Synology memory modules for optimum compatibility and reliability. Synology will not provide complete product warranty or technical support if non-Synology memory modules are used for memory expansion.

Synology website, product specification sheet for the DS220+

Uh oh. A translation to that is: it might be possible to buy third-party RAM, but it might not work properly and Synology definitely will not support you for bugs related to third-party RAM.

So the solution is clear: let’s all buy Synology’s official RAM, right? Well, that brings us onto the first crucial question that we need to answer.

Why Is Synology’s Own RAM So Expensive?

Two equivalent RAM modules side by side for use in a Synology DS220 plus NAS

If I want to add a mere 4 GB of extra RAM to my Synology NAS, I seem to have a couple of options open to me:

  1. Purchase the official Synology RAM (D4NESO-2666-4G) for £100.
  2. Buy third party RAM which is listed as compatible on the RAM manufacturer’s website, such as the Crucial CT4G4SFS8266 4GB kit for… £16.

It’s therefore natural to ask why Synology’s own RAM is so expensive. And the answer is… because some people pay these high price (along with one or two other reasons).

  • While Synology will be manufacturing their own RAM in lower volumes than Crucial and Kingston – resulting in a slightly higher retail price due to supply and demand factors – there is no (good) overall reason why Synology’s RAM is 6x the price of third-party RAM.

    It’s just like how Apple charge over $130 for a Thunderbolt 4 cable, when you can buy third-party Thunderbolt 4 cables for just $20.

    However because Synology make it clear that they will not honor the warranty on your NAS if third party RAM causes issues, some people (rightly) worry and just pay for the official Synology kit.

  • Plus not everyone is a small-time hobbyist. Larger companies purchase a lot of Synology equipment, and many of these companies will have buying policies in place that prevent unofficial modifications and hardware being made to official equipment.

    In other words, Synology’s larger, corporate customers will naturally purchase Synology expansion RAM because their buying managers will not be allowed to purchase unsupported third-party RAM.

  • Finally, Synology have to test their official RAM against each major software release. Just like Microsoft will test various types of hardware out when producing a new operating system, Synology must do the same.

    Otherwise Synology might find that one of their (very expensive) official RAM kits simply doesn’t work with DSM 7.2, for example, which would not be ideal.

    So while Synology could just say “meh, buy whatever RAM you want” and not worry about the occasional NAS crash, they want to ensure that their customers have suitable RAM that doesn’t randomly crash! Which… seems a reasonable policy to me! It’s nice to know that purchasing official Synology RAM should work now, but also in future DSM releases as well.

Does Third Party RAM Work Just As Well?

A Crucial RAM stick that should be compatible with my Synology NAS 1

As long as you purchase compatible third-party RAM, and run a detailed memory test afterwards, there is no reason why you should have any issues. However there is an element of trial and error here with newer Synology NASes, meaning that you might (mistakenly) purchase RAM that leads to crashes – or even data loss.

A Reddit thread from 2020 has dozens of people trying out different third-party RAM sticks in their DS220+ NAS, and not all the tested RAM works. Some users purchased Crucial memory designed for Macs and (unsurprisingly) it resulted in flashing blue lights, and eventually memory corruption errors.

There are even stories online of people’s Synology NASes having frequent crashes after installing third-party RAM, in some cases resulting in data corruption. RAID arrays don’t take kindle to frequent, unexpected crashes, after all.

That’s certainly what scared me a bit when debating whether to purchase official – or third-party – RAM. However I think the general consensus is that you should avoid third-party RAM in a brand new Synology NAS model.

How To Know The Correct Synology RAM To Purchase

If you decide that purchasing third-party RAM is the right choice for you, you’ll naturally want to choose the correct unofficial RAM – so that you don’t have loads of random crashes (and potentially data loss).

Luckily, Crucial have a tool on their website where you input your Synology NAS model, and they tell you the compatible RAM:

The Crucial memory chooser tool on their website

It’s a pretty useful feature, however not all Synology models are available to select here – even when that specific model does support expandable memory.

In this case, Google comes to the rescue! Typing in “[model number] compatible RAM” will usually yield a bunch of Reddit threads confirming the exact model of RAM you need, along with online shops like Amazon listing those exact RAM models:

A few relevant Google results for my Synology DS220 plus

You may need to spend 5-10 minutes of reading, but it should then be clear exactly what RAM will (and won’t) be supported. This approach resulted in me knowing that the 4GB Crucial CT4G4SFS8266 RAM for £16 should work fine on my Synology DS220+:

A Crucial DDR4 RAM stick that can be used in a Synology NAS

PSA: Do You Actually Need To Upgrade The RAM?

I usually get carried away when looking at buying (and upgrading) tech gadgets and computers. That’s why I have a 12-core CPU (the Ryzen 5900X), even though I barely ever need more than 6-8 cores!

If you’re like me, you might also be spending ages looking at expandable RAM for your Synology NAS… even though you don’t actually need to upgrade! So I wanted to finish this article by making two quick points:

  1. Monitor your NAS’ resource monitor at different times of day, and see what your RAM usage is. Unless it is frequently above 70-80%, or you are planning on installing various applications that will use a lot of RAM, you might not need the upgrade.
  2. Remember that your Synology NAS might quickly become CPU-bound. My Synology DS220+ NAS has a 2 core CPU (a Celeron J4025). While this isn’t a bad CPU, it’s fairly low power. If I bought a large capacity RAM stick and somehow got my NAS to work with it, it’s likely that my NAS would become CPU bottlenecked before I use up all my extra RAM.

So while a small upgrade in RAM could make sense if you know that you’ll need it, you might not need a massive, unsupported increase in RAM.

Related Reading: Synology NAS: Turn It Off At Night, Or Run It 24/7 (All The Time)?