The choice of motherboard and CPU was probably the most belabored of all of my decisions. I spent a truly ridiculous amount of time weighing all of the options, creating and comparing different configurations in my Newegg.com wishlist. It didn't help that we're in a transitional moment for processors right now, so at stake in my decision was not only how much processing power I could get for my budget, but also whether the platform I built would be supported in the future, and what amount of upgrade potential I was willing to pay for up front.
A Tale of Three Platforms
It's all Intel's fault. They recently released their Core 2 Duo (Conroe) processor, which by all reports, blows all other desktop CPUs out of the water. While the geek inside me started salivating, I never planned to buy a high-end CPU for my system. My budget just wouldn't allow it. But building a system that supports the current microprocessing champ would guarantee a decent level of upgradability in the future. So the choice seemed simple at first: pair an Intel motherboard with an Intel budget CPU like the Celeron, or even a low-end Pentium 4.
As I did more research, however, I realized it would not be so easy. Even though the Core 2 Duo uses the same type of motherboard as their last generation of CPUs--that is, the same CPU socket (LGA 775 or "Socket T")--most of the existing motherboards do not really support the new chip. The sockets may be the same, but the Core 2 Duo requires new chipsets and configurations. Turns out, to get a Conroe-compatible motherboard would cost a pretty penny.
Another requirement I had for my motherboard was that it be in the Micro-ATX form factor. This would allow me to build a more space-efficient system. Also, M-ATX motherboards typically have built-in graphics engines. As I don't plan on using this rig for gaming, integrated graphics is fine, in fact preferred, as long as the mobo provides TV outputs. But with the pathetic trickle of Core 2 Duo motherboards to the market, my search for an affordable Conroe-compatible mobo for HTPC seemed doomed. In fact, by the time I made my order, the least expensive such M-ATX motherboard that I could actually find, the Intel BOXD946GZISSL, was $90. And with no TV-out I'd have to buy a separate graphics card, a minimum $30.
Feeling burned by waiting for the next-gen platform, I thought, "to hell with upgrading, I'll just buy the cheapest motherboard and CPU that fits my needs." This sent me looking at the AMD Socket 939 platform. Even though Intel's new processor schooled AMD's high-end offerings, AMD's budget processor, the Sempron, is still a better value than Intel's Celeron, and more energy-efficient to boot. And with AMD moving on to a new platform, the Socket AM2, for their next-gen chips, the market is saturated with Socket 939 motherboards and processors. There's a lot of variety in this mature product line, with good values to be found from vendors. In fact, for about the same price as the Intel motherboard and graphics card, I could afford a tricked-out 939 AMD motherboard and a CPU from the mid-range Athlon 64 line of processors. I went to bed one night sure that I had resolved the issue.
When I woke up the next morning, I had nagging doubts. The 939 platform is so cheap because everyone knows AMD isn't going to support it in the near future. What if I get an HDTV and need a more powerful system to handle the HD signal, but find I can't upgrade? And the next-gen platforms of both Intel and AMD use 240-pin DDR2 memory while 939 motherboards use 184-pin DDR RAM. So, if I did upgrade my motherboard in the future, I wouldn't be able to use the memory I buy today. I became convinced I needed to invest in one of the next-gen platforms, even if it came at a premium.
Intel's platform is still too rare and expensive. But AMD's new platform, based on the Socket AM2, has been on the market for a few more months, and it shows in the variety of motherboards available. And sure, Intel is the new speed leader, but AMD will counter soon enough. And even if they never beat the benchmarks of the Core 2 Duo on the AM2 platform, as long as they're competitive, I'll be happy.
The IGP Wars
Realizing that Integrated Graphics, the kind included on lowly business PCs everywhere, outsell high-end video cards on volume alone, computer graphics hardware manufacturers Nvidia and ATI have each moved into that space recently, and not a moment too soon. With more people making HTPCs, and the stiff requirements of Windows Vista, better performing Integrated Graphics Processors (IGPs) are going to be ever more important. And Intel has not been particularly receptive to the needs of HTPC hobbyists with their IGP solutions.
So I resolved early on to go with a motherboard containing either ATI's Radeon XPress 200 or Nvidia's GeForce 6150 GPUs. Both chipsets provide hardware MPEG decoding (to compliment your TV tuner's MPEG encoding), some level of HD acceleration, DirectX 9 support, and the option of TV-output (though not all motherboards exploit this). In the end, the choice was more-or-less made for me. After narrowing down the options to AMD Socket AM2, Micro-ATX, and TV-Out, I had exactly two choices (at least from my preferred vendor):
MSI K9NGM2-FID
ASUS M2NPV-VM
Seems a lot of people are coming to the same conclusion, as various system builder forums are host to comparisons between these two motherboards. I spent a few extra bucks for the Asus, for the simple fact that MSI requires you to buy their TV-Out header separately, so it's a wash on cost and a plus to Asus for convenience.
Crawling Back to Sempron
With the extra cost of the AM2 motherboard, and the premium AMD charges for the CPUs that fit it, my dreams of affording an Athlon 64 CPU were dashed. I opted for the not-quite-bottom-of-the-barrel AMD Sempron 64 3000+, which at least has twice the L2 cache of the 2800+.
So, my choices represent a compromise between current performance, cost, and upgradability. The results aren't perfect, but they'll do. Wait a few more months and I could probably have found a reasonably-priced Core 2 Duo-compatible motherboard, perhaps even with ATI's next-generation IGP, the Radeon Xpress 1250, with full HD support. But that chip is already a few months overdue, and my shows are starting soon!
Next time: The Case
