How much RAM does Unraid need?

How much RAM your Unraid requires depends on your use-case. This article guides you through the different options and tells you, what to look out for.

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As a former FreeNAS (or as it is now called: TrueNAS CORE) user, I was expecting Unraid to require a sizable amount of RAM for an all-round smooth operation. As it turns out, that is not the case as OpenZFS, which is the filesystem TrueNAS CORE uses, and Unraid with the XFS filesystem operate in fundamentally different ways. When used only as network-attached storage (NAS), Unraid’s RAM requirements sit at a modest 2 GB.

When not using Unraid as an application server or virtualization host, the RAM is solely used to load the Unraid operating system from the USB drive at boot. However, if you are building a system with recent components, you might not even be able to find any compatible 2 GB sticks of RAM. That, combined with the fact that you can use your Unraid machine for so much more than just a NAS, is why I recommend you go with at least one stick of 8 GB RAM to start off with.

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Solid aluminium heat spreader
Solid aluminium heat spreader
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Corsair Vengeance LPX 16GB (2x8GB) DDR4 DRAM 3200MHz C16 Desktop Memory Kit - Black (CMK16GX4M2B3200C16)
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16 GB (2 * 8 GB)
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64 GB (2 * 32 GB)
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$209.99

How much RAM your Unraid machine effectively requires depends very much on your use-case. This article will guide you through the different options and tell you what to look out for. There is no one answer to the question: How much RAM does Unraid need?

How much RAM for an Unraid NAS?

As already mentioned, Unraid, when used only as a NAS and nothing more, isn’t very demanding. You will get away with only adding 2 GB of RAM to your system. However, at some point in the future, you might be interested in setting up some Docker containers or spinning up the odd virtual machine (VM) now and again. That is why one stick of 8 GB or 16 GB RAM is the wiser decision than anything smaller to start off with. This also allows you to better expand your RAM capacity further down the line.

How much RAM for an Unraid application server?

Just as they do on your Windows, macOS, or Linux desktop operating system, applications running in Docker containers on Unraid need a certain amount of RAM. Anything from 8 GB to 16 GB will almost certainly cover your needs if you don’t go overboard and only install what you actually need and uninstall or stop applications you are not using any more.

Empty RAM slots on a motherboard used for Unraid
To fill or not to fill (all the available RAM slots)

Keep an eye on your Unraid system’s resources to find out whether your system needs an upgrade or not. Monitoring can easily be done using the web interface or the Glances application, which you can install from the Community Applications. For a better overview and nicer graphs, you can integrate Glances with other applications that might provide an easier to understand web interface, such as Home Assistant.

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G.Skill RipJaws V Series
G.SKILL Trident Z Royal Series
G.Skill Trident Z RGB Series
G.Skill RipJaws V Series
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DDR4
DDR4
DDR4
Size
32 GB (2 * 16 GB)
32 GB (2 * 16 GB)
32 GB (2 * 16 GB)
32 GB (2 * 16 GB)
Speed
4000 MHz
3600 MHz
3200 Mhz
3600 MHz
Latency
CL18-22-22-42 at 1.40V
CL19-20-20-40 at 1.35V
CL16-18-18-38 at 1.35V
CL19-20-20-40 at 1.35V
Cooling
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Aluminium heat spreader
Aluminium heat spreader
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Extras
No RGB
RGB, Intel XMP 2.0 Ready
RGB
No RGB
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G.Skill RipJaws V Series 32GB (2 x 16GB) 288-Pin SDRAM DDR4 4000 (PC4-32000) CL18-22-22-42 1.40V Dual Channel Desktop Memory Model F4-4000C18D-32GVK
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G.Skill RipJaws V Series
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DDR4
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32 GB (2 * 16 GB)
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4000 MHz
Latency
CL18-22-22-42 at 1.40V
Cooling
-
Extras
No RGB
Price
$124.99
G.Skill Trident Z Royal Series [Silver] 32GB (2 x 16GB) 288-Pin SDRAM (PC4-28800) DDR4 3600 CL19-20-20-40 1.35V Dual Channel Desktop Memory Model F4-3600C19D-32GTRS
Product
G.SKILL Trident Z Royal Series
Type
DDR4
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32 GB (2 * 16 GB)
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3600 MHz
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CL19-20-20-40 at 1.35V
Cooling
Aluminium heat spreader
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RGB, Intel XMP 2.0 Ready
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Product
G.Skill Trident Z RGB Series
Type
DDR4
Size
32 GB (2 * 16 GB)
Speed
3200 Mhz
Latency
CL16-18-18-38 at 1.35V
Cooling
Aluminium heat spreader
Extras
RGB
Price
$117.99
G.Skill Ripjaws V Series 32GB (2 x 16GB) 288-Pin SDRAM (PC4-28800) DDR4 3600 CL19-20-20-40 1.35V Dual Channel Desktop Memory Model F4-3600C19D-32GVRB
Product
G.Skill RipJaws V Series
Type
DDR4
Size
32 GB (2 * 16 GB)
Speed
3600 MHz
Latency
CL19-20-20-40 at 1.35V
Cooling
-
Extras
No RGB
Price
$109.99

Reports on RAM usage of Docker containers running on Unraid seem to imply that the requirements aren’t very high. Reddit user /u/Jetboy01 reports that Sonarr, Radarr, Lidarr, Tautilli, Plex, Dolphin, SABnzbd, Deluge, and Pi-hole will run perfectly with just 8 GB of available RAM. Another user in the same thread reports that their 21 Docker containers use just 5.16 GB of RAM.

How much RAM for an Unraid virtualisation host?

Virtual machines (VMs) will be the most demanding use-case when it comes to RAM. You will need to plan what VMs you want to run simultaneously before buying components and purchase RAM accordingly. For example, I wouldn’t dare running Windows with anything less than 8 GB of RAM and would preferably use at least 16 GB. Other operating systems, such as Ubuntu Desktop Edition, will run fine with just 4 GB of RAM.

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32 GB (2 x 16 GB)
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Latency
CL16
CL17
CL16
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Cooling
Heat spreader
Low-profile heat spreader
Low-profile heat spreader
Aluminium heat spreader
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RGB, Intel XMP Ready
No RGB, Intel XMP Ready
No RGB, Intel XMP Ready
RGB, Intel XMP Ready
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Price not available
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HyperX Fury RGB 32GB (2 x 16GB) 3200MHz DDR4 CL16 DIMM (Kit of 2) 1Rx8 HX432C16FB4AK2/32
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HyperX Fury RGB
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DDR4
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32 GB (2 x 16 GB)
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3200 MHz
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CL16
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Heat spreader
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Price not available
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HyperX Fury Black
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32 GB (2 x 16 GB)
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3466 MHz
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CL17
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Low-profile heat spreader
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Price not available
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DDR4
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32 GB (2 x 16 GB)
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3200 MHz
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CL16
Cooling
Low-profile heat spreader
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No RGB, Intel XMP Ready
Price
Price not available
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HyperX Predator RGB
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DDR4
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32 GB (2 x 16 GB)
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3200 MHz
Latency
CL16
Cooling
Aluminium heat spreader
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RGB, Intel XMP Ready
Price
Price not available
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Depending on how many VMs you intend to use and what operating system you will be using, RAM requirements will greatly vary. For multiple Windows VMs, you might have to max out your motherboard’s capacity, whereas Linux VMs without a desktop environment will require significantly less. To get the most out of what you have, I recommend checking whether what you are trying to achieve could be done in a Docker container.

Does Plex Media Server on Unraid need much RAM?

Plex is one of the most popular applications to run on Unraid. I have found many newcomers asking more experienced Unraid users, how much RAM Plex, running in a Docker container, needs. The good news is that Plex doesn’t use much RAM.

However, there are ways of telling Plex to use available RAM as a transcoding buffer. By doing so, switching from play to pause will be done instantly and scrubbing will be way smoother. Transcoding to RAM has the added benefit that you won’t wear out your SSD as quickly, as RAM isn’t susceptible to the same damage as they are. According to reports on the Unraid forums, “a single stream of video content transcoded to 12mbps [takes] up 430 MB on the root [RAM] filesystem”. Thus, having around 8 GB of available RAM for Plex transcoding should comfortably cover all of your transcoding needs.

About Liam Alexander Colman

I first heard of Unraid through the same medium as many of us did: The Linus Tech Tips channel on YouTube. At the time, I was running TrueNAS (or FreeNAS as it was called back then) on my DIY NAS built using a dual-core Intel Pentium G4400 at its heart. I was convinced, I had chosen the better operating system. After all, it was free and open-source and had a large community behind it. One day, after once again facing the need to buy another three hard drives, I seriously started researching Unraid and its features. I bit the bullet and gave it a go, transferring my data on to external hard drives that I later shucked and added to the Unraid array. Since that day, I have not looked back once, and I am now an enthusiastic and experienced user of Unraid. You can find out more about Unraid Guides right here.

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