the nForce2 system is composed of a northbridge and a southbridge... the nForce2-SPP is a northbridge without the onboard video.

the nForce2-Ultra 400 is an nForce2 SPP that has been validated to run at a 200 MHz DDR front-side bus speed (for 200 MHz DDR AthlonXP cpus).

the MCP-T is the nForce2 southbridge that includes the sophisticated nForce2 audio processor. the MCP is the southbridge without the audio.

the best combination for the power user would be the nForce2 ultra 400 northbridge and either the MCP-T southbridge (if you have speakers with a digital input and wish to use the onboard audio) or MCP or MCP-T if you have an add-on card you wish to use, like, say, a Creative Audigy 2.

using the analog outputs of most MCP-T mobos would cripple the nForce2 audio a bit, since the digital/analog decoder is handled by a 3rd-party processor on the mobo (usually C-Media) and the performance of that decoder isn't up to par with high-end Sound Blasters and similar cards. however, the C-Media chip is only the analog decoder; the sound processing is still done by the MCP-T southbridge. using speakers with a digital input completely bypasses the decoder and so the sound of the MCP-T is "purer".

Epox is known for the fastest performance and excellent overclockability with average stability; MSI is known for flawless stability with average performance.