Building an HTPC. Part 3: The motherboard and processor.
Dealing with riser cards
The enclosure I got has a low profile, which is solved on the ordinary way with riser cards, that is, a card that slots into the PCI bus, and has slots out in a right angle to the motherboard. This is complicated a lot by the new expansion card standard, PCI Express, or PCIe. PCIe is not a bus in the ordinary sense, that is, the the slots aren’t just connected with cables to each other. Instead, each PCIe slot talks to the motherboard independently. This means that for PCIe, you can only have one slot in the riser card for each card, which makes the whole riser card business much more complicated.
Even more complicated is the fact that most motherboards today uses a mix of PCI and PCIe slots, and you must have the right type of slot in the right place. The support for PCIe varies for different enclosures, but it has long been standard to have two riser cards, one for the AGP-port, and another for PCI, providing one or two PCI-slots. It’s common for manufacturers to provide an option to change the AGP-port slot for a PCIe x 16 slot, which is what Silverstone does for the LC11. That means that with the PCIe add-on, motherboards that have either an AGP or a PCIe x 16 slot as the first slot and a PCI slot as the second slot will work.
The LC11 also has four USB ports, a microphone jack, a headphone jack and a Firewire port, and a VFD and IR-sensor that requires yet another USB-port, so a board that supports all this would be nice. And since I’m going to use this computer to watch movies, a DVI output and 6-channel audio would be nice to have for the future, even though I won’t use this at the moment.
I would also like to use a cheap and low-power processor. And of course, the motherboard should be cheap too. As mentioned I first looked into mobile on desktop technology, but that wasn’t cheap at all. I then tried with Celeron D processors, because they don’t use much power, and they are cheap, but I couldn’t find a suitable motherboard. Intels Core 2 processors are superfast and low-power, but expensive, so I decided to use one of AMDs Energy Efficient line of processors, which means I needed an AM2 socket.
The mother load. I mean, board
Of course, I couldn’t find any board that fit all of the criteria, but in fact, I found one that fits all of them except one: It doesn’t have a firewire port. But it has 6 internal USB-ports, it includes an extension card with a DVI port, it has the extension ports in the right place, and it was reasonably cheap too: ASRock AliveNF6G-DVI. Shame about the firewire port, but I don’t have anything that uses firewire anyway. The manual for the LC11 says to mount the hard disk and put the hard disk holder back before mounting the motherboard, but there is more space around if you do put the motherboard in while the disk frame is removed.
After the motherboard it’s time for the riser cards. The AliveNF6G-DVI has PCIe in the first slot, so the riser card assembly has to be disassembled, and the AGP card replaced with the optional and 19 euros extra) PCIe riser card. After that they fitted neatly into the motherboard. Also the two cards (the DVI output and a wifi card) fitted well into the chassi without any problems.
I decided on the Asrock motherboard because I wanted to use an AMD Sempron EE processor. After buying the mothercard, I went to the stores that claimed to have processors like that in stock. Well, they didn’t. Finding an Sempron EE was impossible, and I ended up buying an AMD Athlon 64 Dual Core EE 3800+. That is complete overkill for what I need, and the most powerful processor I have ever owned. For what? For watching DVDs and playing music… But at least it only uses 65 watts, so it’s not the usual power hungry AMD beasts. And for 75 euros it’s not as expensive as the similarly low-powered Intel Core 2s.
Next we’ll look at cooling.