How to build your own PC Part 2: Graphics, Case and Power Supply

How to build your own PC Part 2: Graphics, Case and Power Supply

Don't waste your money on an overpriced pre-built PC. We show you how to it yourself.

In Part 2 of our three-part series, we take a look at the ins-and-outs of graphics cards, PC cases and PSUs. [Click here for Part 1


All of Intel’s current desktop processors have built-in graphics, as do AMD’s latest Fusion processors. Older AMD processors have no graphics, but they can be used with motherboards that feature an integrated GPU. So if you’re assembling a PC for desktop use, you may not need a graphics card at all (provided you don't care about high performance gaming).

CPU and motherboard graphics are typically lightweight. If you want to play games, or make use of hardware-accelerated video and 3D-processing functions, a graphics card is still your best bet.

The PCI Express specification has been stable for many years, so if you have an older PCI Express graphics card, there’s a good chance you can plug it straight into a new motherboard and keep using it. Remember, though, that a cheap current card may deliver more graphical power, and generate less noise and heat, than an old high-end model.

If you’re in the market for a new card, there’s a huge range of cards out there, to suit all budgets –check our A-List and reviews. If you’re a serious gamer, you could even invest in multiple cards: to make this work you’ll need a motherboard with multiple PCI Express x16 slots.

Potential pitfalls

Graphics cards can be power-hungry, so if you do go for a high-end card, make sure your power supply can take it. High-end cards also tend to require multiple power connectors, so make sure that your power supply has these available too before investing.

And because graphics cards can get hot, it’s good practice to avoid putting another card directly above it in the case, as the heat could cause that card to fail.

How to install it

Installing a graphics card involves gently pressing it into an available PCI Express slot – although you may need to remove the blanking plate from the rear of your case first to do so.

PC Build 5 Graphics Card 640x480

Then, screw the card’s backplate into place to secure it (on some cases, this will be secured with a clip rather than a screw). On mid-range and high-end cards you’ll also need to plug in one or two power connectors from your PSU. If you forget to do this, when you switch on the computer you may receive an error message, a warning noise or just a blank screen.

Case and power supply

 When choosing a case, size and features are as important as looks. Consider how many drive bays a case offers, and whether it has conveniences such as a front-facing USB and audio connectors. Remember that, in order to use these connectors, you’ll need to choose a motherboard that has internal headers for them to connect to.


Some cases come with built-in power supplies. There’s nothing wrong with these, but they’re typically noisier and less energy efficient than the models that are sold separately.

A 400W PSU will provide more than enough juice for a regular desktop system. You only need a more powerful supply if you’re using at least one top-of-the-range graphics card. It’s best to afford yourself some headroom, though: a power supply that’s running close to its capacity will run hotter and less efficiently.


Modular power supplies let you disconnect the cables you’re not using so that they don’t clutter the inside of your case. Whether that’s worthwhile or not depends on how often you plan to rummage inside the PC.

Potential pitfalls

If you’re a tinkerer, it’s worth investing in a case that affords easy access. If you plan to drive your PC hard, you might want a case with built-in fans to keep things cool. Or, you can buy third-party fans and add them to most cases yourself. In some cases, the positioning of the power supply can make it difficult to mount hard disks and optical drives later on – if you think this might be a problem, skip ahead to the relevant sections and install your drives before continuing.

How to install it

If your power supply is separate from the case, slot it into the cavity at the top rear of the case and secure it from behind with screws.

Next, it’s time to install your motherboard into the case and plug the various case and PSU connectors into it. If your case is cramped, you may want to plug in these connectors before putting the board into place.

The procedure for installing the board depends on your particular case design. With most tower-type cases you’ll want to lie the case on its right-hand side (as viewed from the front), take off the left-hand side and lower in the board so that its USB ports and other connectors line up with the hole at the rear.

PC Build 4 Case 640x480

You may need to screw in metal spacers to set the board at the correct height – these should be included with the case. Make sure they line up with the screwholes in the motherboard.

The board will also come with a backplate cover that you can press into the rear of the case to keep things neat and reduce dust. Once everything is in place, secure the board with plenty of screws.

Now it’s time to connect the power. The large 24-pin connector from the power supply connects to the wide power socket on the motherboard. The plug will fit only the right way round. Four pins at the end of this connector may be separated from the other 20, but you can press the whole plug in as one.

The CPU has its own power connector as well: you’ll find the socket on the motherboard next to the processor itself. There are two standards for this connector; four-pin and eight-pin. The connectors are cross-compatible, however, so you can happily plug a four-pin CPU plug into one side of an eight-pin socket. It works the other way round, too: you can plug an eight-pin plug into a four-pin socket and leave the spare pins hanging off the end.

Finally, hook up the case connectors – little plugs on spindly coloured wires – to the motherboard, to support things such as the power button, hard disk LED, and front USB and audio ports. Ordinarily, these slide onto bare pins sticking up from the motherboard. Check the manual to find the right place to attach them.

What does your PC look like? Show off your photos and see other people's PCs here!



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