Cabling begins
With the exception of the power supply, which we'll tackle in a moment, we now have all the hardware installed in our case. Cabling comes next.
If your case has three-pin power connectors for its cooling fans, you can plug them directly into the motherboard. With some boards, this will even get you temperature-based fan speed control. The motherboard manual should map out all onboard fan header locations.
Cases that use fans with four-pin molex power connectors can't be hooked into the motherboard. Instead, these fans need to be plugged directly into the power supply, which we'll install in just a second.
First, we have a couple of other cables to connect, starting with the one for our optical drive. Depending on the drive, this cable with either be of the IDE or Serial ATA variety. The cable itself should come with your motherboard, and like most PC connectors, it's keyed such that it can only be attached the right way.
Next, connect the hard drive with a Serial ATA cable from your motherboard box. The L-shaped connector only works one way, so you should be able to figure it out.
SATA cables are much thinner and more flexible than IDE ribbons, making it easier to keep cabling out of the way of other components. We'll tidy things up a little later, so don't worry about being too neat just yet.
Power, please
The last piece of the puzzle to fall into place is our system's power supply.
Depending on your case, the PSU may slide in from the back or from the side, and you may or may not have to attach a mounting bracket before it's installed. PSUs feature an asymmetrical screw pattern at the rear to ensure that they're installed in the correct orientation. Line up the screw holes in the power supply with those on the case's rear panel before sliding the PSU into place.
Once the PSU is installed, toss the mess of wires connected to it over the side of the case. This will make running power cables to our components much easier, and we won't need to use all of the PSU's leads anyway.
If you're running a power supply with modular cables, you only need to connect as many cables as needed for the hardware in your system. It's usually easier to connect these cables before dropping the power supply into the system, if only because the area around the PSU can get a little tight in some cases, making it more difficult to plug them in later.
With the power supply securely affixed inside the case, it's time to start our plug fest. First, attach the 24-pin primary power connector to the motherboard. Some PSU primary power connectors can be configured for both 20- and 24-pin motherboards, so make sure you're using the correct setup.
Next, plug the auxiliary 12V connector into the motherboard. Depending on your PSU and motherboard, this will either be a four- or eight-pin connector. As has been the case throughout this build, all connectors should be keyed to fit only one way.
Most modern graphics cards need a little extra juice, so we'll plug them in next. Graphics cards typically use six-pin PCI Express power connectors, although some recent high-end models require eight-pin power.
If your power supply doesn't have the right connectors for your graphics card, check the bundle of cables that came with the graphics card. Power adapters are typically included with retail graphics cards for those running older PSUs that lack PCIe power plugs.
With our graphics cards hooked up, we turn our attention to hard drive power. Serial ATA drives have their own type of power connector, another L-shaped plug that can only be inserted one way.
Some Serial ATA hard drives also have a standard four-pin molex power connector. You can use this connector in lieu of the SATA power connector, if you wish. However, don't plug in both; that can damage the drive.
Finally, we plug in our optical drive using a standard four-pin molex plug. SATA optical drives may use a SATA power connector. Now would be the time to plug in any four-pin case fans, as well.
