Here are the parts you need:
*Motherboard
*Processor
*Graphics card
*Hard drives
*RAM
*Sound card
*DVD drive
*Case
*Power supply
*ATSC Tuner card
Here is the order you should choose your parts:
1. Processor
2. Motherboard (make sure it is compatible with the CPU)
3. Memory (make sure it is compatible with the motherboard)
4. Graphics Card (make sure it is compatible with the motherboard)
5. Hard Drives (make sure your motherboard supports all of them)
6. Sound card, ATSC tuner card, and DVD drive
7. Case (make sure it is large enough for all your hardware)
Processors:
There are two main brands, AMD and Intel. For an HTPC, the Athlon X2 series by AMD and the Core2Duo series by Intel are the best choices. For most HTPCs, the Core2Duo E6600 or the Athlon X2 6000+ will provide plenty of power, and they don't cost too much. The E6600 requires a motherboard with an LGA 775 socket whose BIOS can support Core2Duo processors. The X2 6000+ requires a motherboard with an AM2 socket.
Motherboards:
There is a wide variety of motherboards out there, so choosing one is tough. First, you must have a motherboard with the same socket type that your CPU reuquires. Most motherboards have either Socket LGA 775 or Socket AM2.
AMD X2 6000+ compatible motherboards:
http://www.newegg.com/Product/Produc...ue=710%3A20466
Intel C2D E6600 compatible motherboards:
http://www.newegg.com/Product/Produc...ue=706%3A22731
Your motherboard should also have a PCI-Express 16x slot to be compatible with the majority of modern graphics cards. Also, at least 2 PCI slots are required for the ATSC tuner and sound card.
AMD X2 6000+ compatible motherboards with at least 1 PCI-Express 16x slot and at least 2 PCI slots:
http://www.newegg.com/Product/Produc...lue=735%3A7583
Intel C2D E6600 compatible motherboards with at least 1 PCI-Express 16x slot and at least 2 PCI slots:
http://www.newegg.com/Product/Produc...lue=735%3A7583
There are a few other aspects you can compare motherboards on...
*Form factor (ATX, MicroATX, other?): MicroATX motherboards can fit in smaller cases, but tend to have fewer features.
*Number of SATA channels: The more there are, the more hard drives you can have
*Number of IDE channels: This limits the number of DVD drives you can have (unless you use one of the newer SATA DVD drives).
*Onboard Video: This is only important if you want to avoid using a video card
*Onboard Sound: This is only important if you want to avoid using a sound card
Memory:
Most motherboards use DDR2 memory. You must make sure that you get the same type of memory that your motherboard supports. DDR and DDR2 memory use a different number of pins, so if you get the wrong type, it will not fit. These days, 1GB of memory is the absolute minimum amount you should get. 2GB will serve you for a while, and 4GB is ideal. However much memory you get, it is best to get either 2 or 4 sticks, not 1 or 3. This way you will avoid potential problems, and you will be able to take advantage of the added speed with any dual-channel memory controller. On most motherboards, 2 sticks is the best number to have because it leaves two open slots for easily doubling your memory in the future.
There are different speeds of memory, such as DDR2-677, DDR2-800, and more. DDR2-800 seems to be the best choise right now because it is fast, but not so fast that it is significantly more expensive (like DDR-1066 is). Memory also has different latencies, and the lower the better. DDR2 memory with a CAS latency of 5 is considered mainstream, and lower than that is considered high performance.
Graphics Cards:
The two main graphics processor manufacturers are Nvidia and ATI (now part of AMD). Both make good GPUs (graphics processing units) for HTPCs, but Nvidia GPUs seem to be preferred at AVS. I am not familiar with ATI's offerings, but the Nvidia GPUs best suited for HTPC use include the GeForce 7600GT and 8500GT. The actual cards are made by third party companies like XFX, Chaintech, MSI, Asus, and others.
Because you are into gaming, I recommend either the 7950GT, 8600GT, or 8600GTS. For space issues, the double height video cards are not ideal for HTPC use, and these are the best Nvidia cards available as single height. Because these cards generate quite a bit of heat, I recommend getting an actively cooled version (one that has a fan).
Hard Drives:
There are two common hard drive interfaces: IDE and SATA. SATA is newer and faster, and is becoming the new standard. I recommend getting only SATA hard drives, especially since they cost roughly the same as IDE drives. 320GB and 400GB drives seem to have the best price
erformance ratio right now and cost only 25 cents per GB.
I would not recommend RAID for a first HTPC. A 2 disk setup is probably best for most beginners with one drive containing the operating system and some media, and the second just for media and backups of the OS. Two 320GB or 400GB SATA drives should be able to hold a large amount of media before you need to get more space.
Sound Cards:
Almost all sound cards are PCI cards. They can offer a vast improvement over the on-board sound found on most motherboards. If you can afford it, the Auzentech X-Meridian seems to be the sound card to get for 7.1 audio.
Tuner Cards:
I really can't help you with this one. I suggest you search around AVS for information on tuner cards.
DVD Drives:
These are available with SATA and IDE interfaces. Unless you motherboard doesn't have IDE, I recommend getting IDE DVD drives to leave the SATA channels open for additional hard drives. You can get a good quality DVD burner for $30-$40.
Case:
This must be able to fit all your hardware! It is quite difficult to find the HTPC case you want. If you don't want to go through the trouble of searching for the perfect case, I recommend the Silverstone Lascala SST-LC13-S because it will fit most motherboards, 4 hard drives, and 2 DVD drives.
