10 Mistakes New PC Builders Often Make (Don’t Kill Your New Hardware!)

Building a computer from scratch is kind of easy… but also ‘kinda hard! The big problem is that you can’t know what you don’t know. So here are the top 10 mistakes that I see new PC builders make – and I’ve certainly been guilty of some of these myself!

I discuss some ‘simple’ mistakes (like setting your fans to spin in the wrong direction) and some massive mistakes – like shorting out your motherboard or powering your GPU incorrectly.

I also cover a range of other mistakes in this video, and give tips along the way to avoid these problems.

If you prefer text over video, please read on for the guide/transcript version of this video.

Video Transcript And Guide

Hey everyone, I remember my first ever PC build. It featured an Intel Core i5 750 CPU and an ATI Radeon HD 5850. As a nervous 19 year old I naturally did a LOT of research before attempting the actual build… BUT I still made a bunch of mistakes along the way. Since then I’ve built lots of other computers and here are the ten most common mistakes that people tend to make.

Forgetting Stand-Offs

So the first one I wanted to cover is a BIG one. Don’t get this wrong. Your motherboard has LOTS of wire traces and solder spots on the back of it. These should NEVER touch your case directly since your case is almost certainly metal, and any contact with the motherboard here can and will result in your motherboard shorting out. That’s actually why motherboards have holes on them in various places – it’s so that you can put one of these “motherboard stand-offs” underneath the motherboard, and then you screw it in place. This causes the motherboard to rise above the case and this naturally prevents shorts.

A motherboard standoff and screw
A motherboard standoff and screw

Your PC case usually comes with stand-off screws because each case might have slightly different ‘requirements’ for these stand-offs. Sometimes the screws are supplied in a little plastic bag, but sometimes they are actually pre-screwed onto the case. However some other cases actually have built-in stand-offs that help raise the motherboard away from the case. So do double check your case before mounting your motherboard but it IS still essential to stop the back of the motherboard from directly touching any part of the case.

PSU Switch Is Off

On off switch on the back of my PSU
On off switch on the back of my PSU

The second mistake that people sometimes make is that they finish the build and go to turn their PC on for its first ever boot… and nothing happens. Don’t worry though – double check that the PSU switch is actually turned on. It’s easy to forget this, but power supplies have a physical on/off switch that allows you to isolate your computer from the mains electricity supply of your house. This is mainly a safety thing, even though most of us leave our PSUs on all the time for convenience, but also so that you can set your PC to automatically start on based on your keyboard (or LAN or whatever).

Anywhoo, your PSU’s switch will likely be OFF when you’re first building your computer, so make sure that you flip it so that the line is pressed in – meaning that it’s now ON. Then try booting up your PC again. If it STILL doesn’t boot up though, double check that the front panel connectors are properly hooked up to your motherboard (inside the case). These connectors are really annoying because you need to carefully plug them into the RIGHT header on your motherboard. Yes the cables might be labeled, but it’s still easy to get this wrong. Double check your case and motherboard manuals to make sure that you have connected your case’s power switch wire up to the right place otherwise it ain’t gonna turn your PC on!

Not Removing CPU (Cooler) Sticker

Picture on Imgur showing an Intel CPU with a sticker on it
Picture on Imgur showing an Intel CPU with a sticker on it

The third mistake that some people make – and this especially applies if you’ve purchased a second hand CPU or a “tray CPU” – is to not remove the CPU sticker from the CPU before installing the cooler. Now, the majority of CPUs do not contain a sticker so if you’re wondering what I’m talking about here, don’t worry – your CPU probably didn’t come with a sticker. BUT sometimes “open box” type CPUs do have a little sticker that the store staff stuck onto the CPU.

And that’s ANNOYING because if you don’t remove it, it WILL cause your CPU temperatures to be much, much higher than they otherwise should be. If you find that there’s a little residue of the sticker left after removing it, be sure to clean this off too with isopropyl wipes so that the CPU is as clean as possible before you apply the thermal paste. Your CPU cooler might also come with a plastic film (or similar) underneath it so check – and remove – this before you actually mount the heatsink on top of your CPU.

Plug Cables In First

A Noctua NH C14S CPU cooler installed in my Asus motherboard
A Noctua NH C14S CPU cooler installed in my Asus motherboard

The next two mistakes that I cover requires planning ahead – which is obviously a bit difficult to do if this is your first build, because you can’t know what you don’t know. So, building a PC isn’t TOO difficult – but it does require running LOTS of wires everywhere. Some can be to fairly awkward places too – like the 8-pin CPU power cable, that often routes all the way around your case, to the top corner of the motherboard. Equally the fan headers for your case and CPU fans can be located in awkward spots.

If you have a large CPU cooler or graphics card, it can be almost impossible to reach these fan headers to plug in your cooler or case fans. For example I recently had to completely remove my graphics card just so that I could plug my case fans in (which was really annoying!). What I’m basically saying is that you should know roughly where your motherboard power connectors and fan headers are, and you might want to plug cables into these BEFORE installing your CPU cooler or GPU. It’ll probably save you time in the long run.

IO Shield

The motherboard back panel for my ASUS TUF Gaming motherboard with various ports including USB 3.2 and 2.5 gigabit ethernet
The motherboard IO back panel on my Asus B550M-Plus

The fifth mistake that’s worth knowing is that motherboards often come with an IO shield, which is basically a small bit of metal that goes around all the ports at the back. This shield helps to protect your motherboard from shorts or static damage when plugging things in (like a random USB plug). It also helps prevent dust getting inside your case. Unfortunately this needs to be put into your case FIRST – before you put your motherboard in. I say “unfortunately” because it’s really easy to forget this – again, you don’t know what you don’t know. I actually forgot the IO shield in my first ever build… and also my second one.

Honest, I got it wrong twice, so I literally had a big gaping hole in the back of my case for quite a few years. Luckily many motherboard manufacturers have recently started building the IO shield into the motherboard itself, which is useful, but not all motherboards have this. So if you see a random bit of spiky metal during your build, make sure you mount it to your case as soon as possible!

RAM Insertion

The sixth thing that people often get caught out by is how to correctly push the RAM into the RAM slot. It actually requires a decent amount of force, and you can feel the motherboard bending a bit when inserting the RAM – which is scary.

A close up view of Corsair RAM a Noctua CPU cooler and the end of a graphics card
A close up view of Corsair RAM, a Noctua CPU cooler and the end of a graphics card

It’s always hard to know the difference between “correct force” – and too much force that ends up breaking something. What I WOULD say with your RAM, though, is that you should see the little clips moving TOWARDS the RAM while you’re pushing the RAM in. This is a sign that you’re correctly inserting the RAM. The clips should then fully close around the RAM once you’re done. If they don’t close, push harder – your RAM isn’t all the way in (sorry!). One note of caution though – before you get started, just make sure that your RAM is going in the right direction – there will be a little notch on it that is just off center, and this needs to line up with the motherboard’s RAM slot (which is also off center).

Corsair RAM with a removal will void warranty sticker
Corsair RAM with notch near the halfway point

Naturally don’t push the RAM in with force if it’s not lined up properly, otherwise this WILL break things.

Case Fan Direction

The next mistake that some people make is to accidentally install their case fans in the wrong direction. Case fans often (but not always) have little arrows on them that tells you what direction the air will flow through them. If the arrow is facing into your case, the fan is acting as an intake – it will be bringing NEW colder air into your case.

A case fan with direction arrows on it
A case fan with direction arrows on it

If the arrow is facing out of your case, it’s an exhaust fan – and it will be blowing warmer air (from your CPU and GPU) out of the case. In the majority of cases you want your bottom and front fans to be intakes, and your top and back ones to be exhausts. So do double check that your fans are facing the “right” way. Sometimes people find out that all their fans are constantly blowing air out their case (y’know, every single fan!) which is known as a negative pressure set-up and this often isn’t ideal.

Don’t Drop It (Linus!)

Dropping a screwdriver onto my motherboard 1
Dropping a screwdriver onto my motherboard 1

The eighth mistake I wanted to cover is to be careful not to drop things onto your motherboard! So many people use their phone’s torch as a light, for example… and then they drop the phone onto the board, potentially damaging it. Or they buy a fairly heavy screwdriver… and then drop this. So if you have Linus’ gravity attracting tendencies, then here’s two suggestions for you. Instead of using your phone’s torch, either try and build where there is an overhead light. OR you can look to buy a head-based torch. Yes it might look a bit weird at first, but needs must.

Dropping things onto your motherboard (or your freshly installed CPU) is never good! I also usually use small, lightweight magnetic screwdrivers when building PCs. They are MUCH lighter than ratchet screwdrivers and so they’re less likely to break something when you drop them.

Bypassing Your GPU

A HDMI cable plugged into the motherboard not my graphics card
A HDMI cable plugged into the motherboard not my graphics card

The next mistake that people sometimes make is to buy a really expensive graphics card for high res gaming, but then mistakenly plug the monitor’s cable into the motherboard. Yeah, so that won’t work. I mean, it WILL work if your CPU has integrated graphics but the problem here is that you’re bypassing your graphics card, essentially. So if you’re experiencing poor gaming performance on your flashy new build, please quickly double check that the DisplayPort or HDMI cable is plugged into your GPU and not your motherboard.

Underpowering Your GPU

Running PCIe power cables below the GPU
Running two PCIe power cables to the GPU

The last tip I wanted to cover is HOW you power your graphics card. There was a time when graphics cards were fairly low power, and they could often be powered just by your motherboard’s PCIe slot that supplies 75 watts. However nowadays graphics cards are power hungry, meaning that you need to plug PCIe cables into them directly from your power supply unit. Some PCIe cables come with this horrible “pigtail” connector and these SHOULD work okay for graphics cards that need less than 225 watts of power, but in general you should be running multiple, SEPARATE PCIe cables to power your graphics card – don’t just rely on the pigtail connector. This is a whole other topic and I discuss it more in another video, but I wanted to specifically mention this mistake because it’s an easy one to make.

cropped A picture of me Tristan
About Tristan Perry

Tristan has been interested in computer hardware and software since he was 10 years old. He has built loads of computers over the years, along with installing, modifying and writing software (he's a backend software developer 'by trade').

Tristan also has an academic background in technology (in Math and Computer Science), so he enjoys drilling into the deeper aspects of technology.

Tristan is also an avid PC gamer, with FFX and Rocket League being his favorite games.

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