These 4 PC building mistakes actually make your rig worse

• Applying too much thermal paste, or not enough
• Bad cable management
• Choosing a weak or barely adequate power supply
• Going overboard with lights or cooling

Having worked on a few custom PCs of my own, I know that while the process doesn’t have to be intimidating, you do have to stay alert. Things that don’t seem like they might be an issue at first can occasionally slow the process down, or force you to re-do a step when you try to boot and nothing happens. Things were arguably worse before PCIe and M.2 slots were standard — I remember struggling to hook hard drives up to long, snaking SATA cables.

What’s actually more troublesome is a mistake that results in a functional PC, but one with a sub-par experience. In some circumstances, you may just be postponing system failure. These are some of the gaffes you need to be prepared for if you’re going to go the custom route, whether you’re aiming for a monster gaming PC or just trying to save money.

Applying too much thermal paste, or not enough

The right balance isn’t too hard

You’d think thermal paste wouldn’t be that hard. We’re in the 21st century, so it’s strange in a sense that smearing goo is required at all. Simultaneously, though, you’d assume that it’d be better to lean on the side of applying too much, given that the idea is to eliminate every air gap and improve heat sink efficiency.

The truth is that there’s a delicate balance. Yes, you need enough paste to eliminate air gaps, but too much can form an insulating layer, actually intensifying heat. And for obvious reasons, you don’t want paste seeping over the edges of your CPU and cooler into the surrounding motherboard.

Regardless of which shape you use, you don’t need very much to achieve complete coverage.

There are three schools of thought on the best way of applying paste. My personal preference is for a pea-sized dot in the middle (as shown), which will naturally spread out when it’s clamped down on. Other people choose to draw a small line, and still others will draw a small X. Regardless of which shape you use, you don’t need very much to achieve complete coverage.

The good news is that once you’ve applied the proper amount of paste in your initial build, you may never need to re-apply it unless you run into unexpected heat surges, or you keep your PC active for more than three to five years.

Bad cable management

Remember, you’ll be back

As I noted earlier, cable management used to be a bigger issue in custom PCs. Hard drives had to be mounted into bays, so the only way of connecting those drives with the rest of your system was a snaking bundle of SATA and power connectors. In retrospect, fighting with that bundle was the thing I hated most. Modern PCs are miraculously clean, by comparison, thanks to the adoption of slot-based architecture for the most important parts.

Often, simply taking advantage of zip or velcro ties will make things neater, and remind you which cables are supposed to be together.

There are still cables to deal with, of course, and it’s important to get management right — not so much for your initial build, though, as when you need to open your PC back up. Cables in the wrong place can make it difficult for your fingers to maneuver, or even prevent you from installing new parts. If you’ve got a transparent case, as many PC gamers do these days, a nest of wires is going to look a lot less attractive than something organized from the outset.

Often, simply taking advantage of zip or velcro ties will make things neater, and remind you which cables are supposed to be together if there’s any chance of confusion. With some towers, you may be able to clip or tie cables to the frame, which is a wise idea — as long as you make it relatively easy to undo your work. You never know when you’ll need to re-open your PC to fix things or swap components.

Choosing a weak or barely adequate power supply

Give yourself some flexibility

It’s possible to go totally overboard with a power supply. No one needs a 1,200W brick like the one above, except perhaps the people who can afford an Nvidia RTX 5090, which will probably cost as much or more than the rest of the PC it’s sitting in. Better supplies also occupy a lot of space, which can create more problems than they solve if you don’t have a giant tower on your desk.

That said, it’s important to not just match your power supply to the combined wattage of your CPU and GPU, but exceed it at least a little. If your PC is ever underpowered, that can lead to instability, shutdowns, or component damage, assuming it boots in the first place. When power is sufficient, but no more than that, you won’t be able to overclock anything or upgrade to a faster GPU. Personally, I budget for at least 100 to 200W more than the baseline suggested by PC parts makers.

​​​​​​​If your PC is ever underpowered, that can lead to instability, shutdowns, or component damage, assuming it boots in the first place.

As a side note, it’s worth pointing out that an oversized supply won’t automatically consume more power or generate more heat. It’s only ever going to deliver as much wattage as a PC demands, and it should actually run cooler, since it doesn’t have to work as close to peak capacity. Think of it like an e-bike — the model rated for 5000W will barely exert any effort going uphill, whereas the 250W one will be using all that wattage at every second.

Going overboard with lights or cooling

It’s about time, value, and tackiness

This pick is bound to be controversial for a few reasons. For one, more cooling is almost always preferable, since it prolongs the life of components and allows for overclocking. Some people also resent the idea of anyone recommending how they should personalize something, as if they were receiving orders. I’m just making suggestions, to be clear — it’s up to you to use your best judgment.

There are a few potential problems with excessive lighting and cooling, the first of course being cost. You can spend hundreds of dollars on it — which won’t a barrier if you’re rich, but there’s always the question of value. $100 or $200 extra spent on lights or an overpowered AIO cooler could potentially go towards things like a bigger monitor, a faster GPU, or extra storage. Simply getting a better mouse or keyboard can save you the grief of bad ergonomics or stuck buttons.

The more elaborate your PC’s internals are, the more complicated they become to fix and change.

Also, the more elaborate your PC’s internals are, the more complicated they become to fix and change. You may not mind this, and may actually enjoy it if you consider building part of the fun. If you don’t, though, you’ve actually increased the burden of maintaining your PC.

Use moderation, in other words. Personally, I wish more people applied that to aesthetics as well. Some gaming PCs can become rainbow-colored neon nightmares with no theme other than “I can afford this.” You do you, but it’s often the subtler designs that impress me the most.