In Part Three 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 and here for Part 2.]
Hard disk/SSD
Most hard disks sold in the past five years use a standard SATA connector, so you can connect an old one to a new motherboard. If you want to keep a drive that uses the older PATA bus (also known as IDE), you may have to shop around for a motherboard with this connector, since it’s no longer standard. Or invest a few quid in a PCI Express IDE card.
If you’re buying a new drive, you have options. Big disks are affordable – our A-Listed 2TB model costs less than $80 (but has increased lately following the floods in Thailand). Some premium models support the SATA 6Gbits/sec interface – although in our tests, we’ve yet to see a mechanical drive that derives a measurable benefit from this.

If performance rather than capacity is your primary concern, consider a solid-state drive. Such drives won’t necessarily speed up your work, but they make it quicker to open and switch between applications.
SSDs are far more expensive than mechanical disks. A popular compromise is to buy a small SSD for the operating system and a larger mechanical drive for personal data.
Potential pitfalls
If you move your Windows system disk from an old system to a new one, it might not start up, since it’s configured for completely different hardware. You can sometimes get around this by going into the BIOS and switching your motherboard’s drive controller from AHCI to IDE (or “legacy”) mode, or by running a repair routine from the installation disc. If that doesn’t work, you’re out of luck – and it may not be legal to use your old installation on your new PC anyway.
If you want to run Windows from an SSD, perform a clean installation to the drive. This ensures Windows will use the TRIM feature and settings that are appropriate for solid-state storage.
How to install it
If you’re using a 3.5in disk, simply slot it into a spare bay in the case, connect it to the power supply and use a SATA cable to connect it to a spare SATA port on your motherboard. (You may prefer to plug these connectors in before inserting the drive into the bay.)

Drives become hot in use, so if you have spare bays it’s a good idea to pick one that leaves plenty of breathing space around the disk. Screw the drive into place, using two screws on both sides to secure it.
SSDs use the same connectors as regular drives, but high-performance models are often fast enough to benefit from SATA 6Gbits/sec. If you have such a drive, make sure you connect it to a high-speed SATA port on your motherboard or you won’t get the benefit.
Since SSDs are physically smaller than regular desktop drives, your case may not have a suitably sized bay. Some drives come with a cradle that lets you fit the SSD into a 3.5in bay: failing this, you can use two screws to secure it to one side of a bay.
This isn’t a perfect solution, but SSDs are very light, so it shouldn’t be a problem – and it’s better than having the drive rattling around inside the case.
Memory
All modern desktop motherboards use DDR3 memory. This has only become popular in the past few years, so even if you have an older PC it’s likely you’ll be buying new memory for your new system.
For less than $40, you can get a 2GB memory kit containing two 1GB DIMMs (on almost all platforms you get the best performance when you add identical DIMMs in pairs).
This is enough memory for Windows 7 and most applications to run smoothly, and for only a few quid more you can move up to a 4GB kit, which offers a good degree of headroom for the future. Currently, we’re not aware of any everyday applications that derive a tangible benefit from more memory than this, but we’re sure they’ll come soon enough.
You can spend extra on high-speed RAM, but in most cases that’s a luxury: in our benchmarks, we’ve found that doubling the memory speed gives desktop applications an average performance boost of only a few per cent. However, if you’re using an integrated GPU that uses shared system memory as a frame buffer, faster memory can deliver a few extra 3D frames per second to give you a smoother gaming experience.
Potential pitfalls
Some cheap motherboards have only two RAM slots: if you fill these with two 1GB DIMMs, you’ll have to throw those DIMMs away if you want to upgrade the memory later on. That’s worth considering when you’re choosing a motherboard or a RAM kit.
You should also be aware that 32-bit Windows won’t recognise more than around 3.5GB of RAM. This means if you have to use a 32-bit OS – perhaps for compatibility with older hardware – there’s no point buying any more than 4GB. The 64-bit edition of Windows 7 Home Premium can support up to 16GB of memory, with the Professional and Ultimate editions supporting up to a rather generous 192GB.
How to install it

DIMMs push into the colour-coded slots: put your two modules into slots of the same colour. Clips at the sides of these slots hold them in place.
The slots have a notch in the bottom of them to ensure you’re putting the modules in the right way round. If the DIMM won’t fit either way round, you’re probably trying to put a DDR2 DIMM into a DDR3 slot (or vice versa).
Optical Drive
These days, it’s possible to get by without an optical drive, but you might occasionally want to rip or burn a CD. Optical drives haven’t changed much over the past few years, except that many now play Blu-rays (be aware, though, this requires third-party software).
You can get Blu-ray writers for around $100, but we’re not convinced they’re worth it: the 50GB discs cost a few dollars each, so it’s much cheaper to use an external hard disk for storage.
Potential pitfalls
If you want to bring an optical drive across from an older PC, the same issues apply as with a hard disk. If your drive has a SATA connector you’re good to go, but if it uses PATA your new motherboard may not be equipped to support it.
The positioning of the power supply can also make it difficult to install the optical drive – you may need to temporarily unscrew it to get the drive in.

How to install it
In most cases the optical drive bays can be found at the front, at the top. In some the drive slides in from the front: if your case is like this you’ll probably need to pop off the front panel and remove a blanking plate to get it in. In other cases, the drive goes in from behind, but you’ll still need to remove a plate at the front of the case.
Once you’ve slid the drive into its bay, you can screw it into place. If your PC case has a built-in eject button, make sure the drive isn’t too far forward or back, or this button may not properly connect with the drive’s own eject button when pressed.
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