Build a Linux PC ( part 3 )

Power supply

One of the most overlooked components is the power supply (PSU). Avoid the cheap PSUs that are included with cases (in fact, avoid cases that are cheap enough to include a PSU). A PSU must be reliable and good quality. That may seem an obvious statement that applies to all components, but when a PSU fails it can do so in a way that takes out other components.

Having a £100 motherboard or hard drive, or both components, wrecked by a £15 PSU is not a good way of saving money. Other aspects to consider when choosing a PSU are: that it must supply sufficient power for your needs, now and in the future, that it is efficient (any PSU worth its salt is rated 80 Plus, but look for Gold, Platinum and Titanium models) and that it’s quiet (particularly for a living room computer).

 

There are several websites where you can list the components you are using and get a recommendation of the power supply you need, for example http://support.asus.com/PowerSupply. aspx?SLanguage=en. Check that the PSU you choose has connectors you need, most motherboards take a 24+4-pin ATX connector and a separate CPU power lead.

Also ensure you have enough drive power connectors of the right type, some PSUs still come with more of the old Molex connectors than the useful SATA power plugs. If you are using a large case with a bottom mounted PSU, check that the leads are long enough to reach the drives at the top, although you can buy SATA power extender leads cheaply enough that deal with the last two points.

You’ll be pleased to know there are no special considerations to be taken regarding Linux compatibility!

Specialised systems

So far we have looked mainly at a general purpose desktop system, but there are some specialist users to consider, such as a home server or a high-performance gaming systems. If you want to build a home server, your requirements will be very different from a desktop or gaming system. As all data is transferred over the network, a fast SSD is pointless.

You could use one for the operating system, but servers are rarely rebooted, so you wouldn’t even benefit from the fast boot speed they offer, and they only run a limited number of programs, so loading time is not that important either. Servers generally run headless, so a fancy graphics card isn’t needed either, you only need a monitor for the installation process and the onboard graphics of most motherboards are more than suitable for that job.

What you do need is a decent amount of memory and plenty of storage space. If you are building a file or media server, pick a motherboard with plenty of SATA ports and a case with a similar number of drive bays. However, much storage you add, at some time you will want more.

If you are building a web or mail server, storage space is not such an issue, unless you want to serve media files over an internet connection, but plenty of memory helps, especially with Apache . Another type of home server is a media server. This could simply be a repository for your video files or you could be doing the recording on the server too, using MythTV backend server software or something like Tvheadend.

Either way, you will need plenty of space. If you have a server that transcodes video too, maybe something like Plex that reformats video to suit the device playing it and the speed of its connection to the server, you will need a decent amount of RAM and a reasonably fast CPU – not a gaming monster but something that’s not budget.

As everything works over the network, it goes without saying that it should have a fast network interface, especially if more than one client will be using it at the same time, so make sure it has a gigabit interface, or budget for a decent PCI-e network card.

High-performance gaming

Gaming, and we mean the graphically intense kind and not gambling, places specific requirements on a computer. Performance is the obvious factor, but not just the performance of the CPU. The GPU on the graphics card plays a more important role than the CPU with some games.

Clearly you want a fast CPU and graphics card. Many of the higher performance graphics cards take up the space of two PCI-e slots so you need to make sure both your computer’s case and motherboard have room for it and that your PSU is capable of powering it in terms of raw power and physical connectors it can offer.

Memory is also important, you want plenty of it and the fastest available. Disk storage space is less important than speed, so an SSD is the preferred choice for storage.

Gamers always want more performance and one of the ways of getting it is by overclocking their systems. This is where you run your processor and memory at higher than its rated speed. For general purpose use, opinions on overclocking are divided; it does give better performance but at the cost of possibly shortened component life and unreliability if you push it too far, plus more heat to get rid of.

Some CPUs are locked at a particular speed, so you need to make sure the processor you choose is able to be overclocked. You also need a suitable motherboard. They all offer some control over frequencies and voltages, but some motherboards are intended for overclockers and offer far more control – you’ll need to do your research carefully. To deal with the extra heat, you need a good sized case to maintain plenty of airflow, combined with a decent CPU cooler (the stock cooler supplied with the CPU isn’t intended for overclocking) and plenty of fans.

A motherboard intended for overclocking may have more fan connectors and some speed control for them. When choosing cooling fans, go for the largest you can fit. A larger fan shifts more air; fast spinning fans create more noise. If noise is an issue, consider water cooling.

Overclocking used to be a specialist field that required you to buy and assemble various components then spend ages bleeding the system and performing leak tests (it may surprise you, but water and electronic do not mix well). Nowadays pre- built units are available where you bolt the radiator assembly to a suitable point on the case and clip the heat sink in place of the CPU fan.

Some kits also include GPU coolers; as mentioned, gaming works them hard too. Water cooling is not only for gamers and overclockers, it can be use on a standard desktop system to reduce the noise. The loudest noise from such a setup comes from the hard drive stepper motors.

Sealed systems

Assembling a desktop or server computer is a fairly straightforward task, creating your own laptop isn’t. While it’s possible to buy laptops piecemeal, it’s not the usual way of doing things. Still, much of what we have covered in this feature still applies. It is just as important to choose suitable components for a laptop; even more so really because you cannot simply swap them out if you don’t like them. So it is a matter of finding a pre-built laptop within your budget that meets your requirements and then checking that everything will do what you want it to. The same applies if you are looking for a nettop to act as a media player. The same rules apply for choosing a suitable processor, graphic card, sound card and so on (although the use of the word ‘card’ here is not strictly correct, almost everything is on the motherboard).

There are a couple of important differences: laptop hard drives tend to be slower than their desktop counterparts, making the speed advantage of an SSD even greater. Memory upgrade options are limited, so choose a device with plenty to start with and make sure that it has at least one free slot for expansion. Some laptops have only one slot so upgrading memory means throwing away what you have rather than adding to it. If you have the option, try booting the laptop from a recent live CD, or a live distro on USB.

System Rescue CD with the Alt kernel option gives a very recent kernel with the most up to date hardware support. Run $ ifconfig -a to see that both wired and wireless interfaces show up and use $ aplay to make sure the sound system works all the way from the given file to the speakers.

Wireless interfaces can still be a problem with some laptops, but most have a mini-PCI slot these days, in which case you can try another card. While the Intel vs AMD CPU war and the Nvidia vs AMD graphics war will continue to rage on, Intel provides excellent support for its components. If your laptop has both Intel graphics and wireless cards, it won’t go far wrong and everything should just work with no need to install extra drivers. Now grab your favourite distro and enjoy the speed and freedom of Linux!

Installing an operating system

Once you have built your computer, you will need to install an operating system. We will not look at that here, the distro installers are well enough documented, but there are a couple of points to consider. New motherboards will use UEFI rather than the older BIOS. They may also have Secure Boot enabled.

You will almost certainly need to turn this off in the firmware. Press the relevant key at boot to configure the firmware, the motherboard’s manual will tell you which it is (one of the joys of building your own computer is that you get a manual for your motherboard). You should be able to use UEFI to boot the computer, most distros now work with it, and it’s nicer to work with than the old MBR system.

If you need to use MBR booting, there will be an option for this in the firmware menu. Some have a UEFI boot option that you can turn off, others have the cryptically named CSM (Compatibility Support Module) that has to be enabled for MBR booting.

If you are building a Linux-only system, you can just boot from your favourite DVD and install. If you want to dual boot with Windows, you should install Windows first and then Linux. The Linux installer will pick up the Windows installation and set up a dual-boot menu, whereas the Windows installer would just trample over the Linux bootloader if you did things the other way round.

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