How to Build a Small Mini-ITX PC

Ready to build a new PC but have limited space and a limited budget? It’s time to consider the Mini-ITX form factor. Compact motherboards measuring just 170mm by 170mm could revolutionize how you use your computer.

As with any PC build, you need to have the right components carefully chosen for compatibility. Here’s everything you need to know about building a powerful and compact PC using the Mini-ITX form factor.

Used for PC with ITX form factor

Building a small Mini-ITX PC is ideal for several purposes.

Compact desktop
Creating a media center or Home Theater PC (HTPC)
To run as your own data or media server
As a dedicated gaming PC

Below are instructions for building a standard, low power, compact desktop computer. For a dedicated HTPC or gaming PC, you can choose to add a dedicated graphics card. Likewise, if you’re building a server, you’ll probably choose the maximum number of storage options.

What You Need for an ITX Mini PC

Regardless of size, building a PC has the same basic requirement: ensuring hardware compatibility.

Mini ITX motherboard

For a Mini-ITX PC, you’ll need a suitable 170 x 170mm motherboard, as well as a low-profile heatsink and fan. Looking for a more intense gaming experience? Look for a powerful enough GPU to suit the occasion.

The PC shown in this guide has the following components:

Case: Cooler Master RC-130-KKN1 Elite 130
PSU: Corsair VS450
Motherboard: ASRock AB350 Gaming-ITX/IC
Processor: AMD Ryzen 3 2200G with Radeon Vega 8 graphics
RAM: Ballistix Elite 4GB DDR4
HDD: SanDisk SSD PLUS 120GB Internal SSD

The total cost of this inexpensive build was less than $500. Your build may be more complex. Be sure to check out help as well.

Building an ITX mini PC in 10 steps

Be sure to read the documentation that came with your motherboard and case before proceeding. Understanding which device goes where, which jumpers to use, and how to properly set up the BIOS will help solve most of the problems that arise when building a new computer.

You are going to build a small computer, but the general principles of building a standard desktop apply. Our downloadable guide on how to build your own computer. provides a more detailed approach.

Step 1: Order spare parts, check for compatibility

You have already settled on a Mini-ITX case, so now you need to choose the hardware that suits your requirements and budget.

Beware: It’s easy to order the wrong parts. The motherboard, processor and RAM modules must be fully compatible for the computer to work. Thus, you must use an online compatibility tool.

Crucial Offers RAM and Motherboard Compatible ‘Advisor’ Tool
Intel dedicates part of its hardware compatibility site
PC Part Picker is an excellent independent resource for purchasing compatible components

Once you have checked, check again. Place an order only after making sure that the equipment is working and you have studied the satisfactory reviews.

Step 2: Prepare your antistatic workspace

Before unpacking the parts, take the time to clean the work area. Wipe it free of fabrics and loose metal. Then ground yourself with an anti-static wrist strap.

Then, unpack the motherboard by placing the anti-static bag on one side.

Place the motherboard in the foam antistatic bag (NOT the antistatic bag) it came with before proceeding.

Step 3: Install the processor

Processor installation

Here’s how to safely install the processor:

Release the latch on the processor socket. This will either be a lever or a cover that pivots over the processor and locks it in place.
The processor will only sit in one direction. Each pin on the underside has its own individual socket, so it is very important that the processor is properly oriented. You will probably notice a small triangle at one corner of the processor; this will match the similar symbol on the motherboard’s CPU socket. Make sure the processor is installed in the socket before continuing.
Secure the processor in place using the bracket or cover. If you installed the processor correctly, no effort is required.

This three-step process ensures safe and accurate installation. The processor setting will differ depending on the type of socket.

Step 4: Attach Heatsink and Fan

Install Heatsink and Fan on Mini-ITX PC

It is vital that the processor stays cool, which means adding a heatsink and fan to dissipate heat.

However, there is one more element: thermal paste. In most cases, the heatsink and fan come with pre-applied thermal paste. This means you don’t have to worry about applying the correct amount to your CPU and the complications that can come with it.

Follow the instructions provided to mount the heatsink and fan to the CPU, making sure they are securely in place.

Step 5Install RAM

Proper RAM installation is vital. Without this, the computer cannot work. Incorrect installation can short out the RAM module as well as the motherboard.

When installing RAM, make sure the entire module is fully inserted into the slot. Everything must be on the level; You don’t want to see any pins above the slot. Also, the fasteners at both ends of the module will lock into place when the module is fully inserted.

If you are using multiple RAM modules, they should be the same type and size for best performance.

Step 6: prepare the case

Install the I/O shield into your PC case

You are almost ready to install the motherboard into the case. Start by screwing four risers (also known as standoffs) into the case where the motherboard should be.

Once this is done, you need to install the motherboard I/O shield. This is a metal frame for the ports on the back of the case. You must install it in place before installing the motherboard.

Step 7: Install the Motherboard into the Case

Attach the motherboard to the case

With everything set up on your motherboard, it’s time to install it in a Mini-ITX compatible case.

Carefully lift the board and slide it into the case, being careful to align it with the risers and the I/O shield. The back of the case should line up with the ports on the motherboard.

Once the board is in place, secure it in place with the dedicated screws.

Step 8: Add a Power Supply

If the case does not have its own power supply, you will need to install one. This can be problematic for Mini-ITX cases, so you need to choose either a compact PSU or a case with extra space for a standard PSU.

After installing the power supply, connect the cables to the motherboard as instructed in the board’s manual. It should be obvious where to connect the cables. The motherboard is powered by ribbon cables, while the processor and fans have separate power cables.

The rest of the PSU cables are for storage devices.

Step 9: Mini PC Test Boot

At this stage, it is recommended to check that everything is working. You should have already double checked the connections, so plug in your PC and turn it on. Don’t forget to turn on the power supply before pressing the button on the front of the case!

When your computer is connected to the monitor, you should see the initial POST (Power On Self Test) screen. Part of it is scanning a drive that you haven’t connected yet. If you’ve made it this far, you should see the CPU displayed correctly, along with the total amount of RAM.

Hold down the power button to turn off your computer and unplug it. You are ready to install the storage device and operating system.

Step 10: Plug in your hard drive

Connecting a drive (SSD or HDD) to the motherboard is relatively simple. You just need to connect the SATA data cable from the motherboard to the drive; then connect the power cable to the drive. You also need to secure the drive in a suitable slot.

However, if your motherboard supports M.2 SSD boot storage, you can use that. While this will slightly increase the cost of your build, it will provide much faster transfer rates and improved performance.

Note. At this point, whatever Blu-ray drive (or other optical device) you plan to use should be installed. Optical drives are connected in the same way as drives.