In terms of performance, today's motherboards usually differ from one another only by about 5%, so they rely more on special features and add-ons to distinguish themselves from the competition. Let me first summarize on standard features before talking about the interesting add-ons.
All candidates are standard ATX motherboards and come with the following features:
- Support for all Duron and Athlon models (Thunderbird and Palomino)
- Support for 100 and 133 MHz FSB (200/266 MHz DDR) and PC1600/PC2100 DDR memory.
- Support for CL2 and CL2.5 unbuffered DDR memory, 64 or 72 Bit (Parity)
- AGP 4x
- at least 5 PCI slots
- at least two UltraATA/100 ports
- four USB ports (two controllers integrated into the South Bridge)
- at least two DIMM sockets
- Wake on Modem, Wake on LAN
- two serial ports, one parallel port
A very attractive feature is a sound system. There are two ways that manufacturers can integrate this: Either place an AC97 sound codec onto the board, or include a separate dedicated PCI sound card. The first method puts extra burden on the CPU, which was a very real problem some years ago, but today's processors are definitely able to cope with the sound output of several stereo channels. Similar to having the separate PCI sound card, motherboard manufacturers may opt to put a dedicated PCI sound chip on the board - this lets you have extra features without increasing the CPU load. However, nobody actually does this because of high costs, so if you want to have any kind of really sophisticated sound system (e.g., with Dolby Digital 5.1 surround sound), I'd recommend getting a separate PCI sound card.
Many companies offer motherboards that have two BIOS Flash ROMs. The only advantage of such boards is that you easily can recover from a BIOS failure. Flashing it is still a risky affair: Even a short power failure can have the BIOS update procedure fail (that's just another reason for getting a high-quality power supply!). In this case, motherboards with a backup BIOS only need to be switched to the secondary one in order to restore a working system condition.
There are also hardware features that are useless for most users. I am talking about AMR (Audio Modem Riser) or CNR (Communications and Network Riser) slots. The basic idea of such a multi-purpose interface may be good, but there is hardly any hardware available for those slots. I prefer to have a sixth PCI slot instead of AMR/CNR.