hi im new here...nice to meet you girls and guys~

i am building my own computer.
the stuffs i have in my mind so far are:

Processor: amd athlon 64 X2 4200

Motherboard: Socket AM2 NVIDIA nForce 570 SLI MCP ATX AMD or
Socket AM2 NVIDIA nForce 570 Ultra MCP ATX AMD
whats the difference and which has better performance?

Video Card: geforce 8600 GTS

Memory Card: 1Gb 240-pin ddr2 sdram ddr2 1066 (pc8500)

Hard Drive: 120GB or i will upgrade it later (if i have to)

Sound Card: i have Sound Blaster PCI 128 or ill get Sound Blaster X-fi xtremegamer

Power Supply: 400w Bean Tech or 400w ATX V12
which is better?

Hi fkyounggs, welcome to the PCHF.

First of all, i do believe the CPU you have chosen, and the 2 mothers you've got - do not support each other. They are the same socket, but the x2 4200 is not an AM2..unless there's information there that's been left out - but i don't remember seeing an AM2 4200+...i could be wrong

In regards to the motherboards, the first one, is an SLI motherboard - supports 2 video cards. The other only supports 1. I'd go with the SLI board personally, for any sort of "future" plans.

I'd suggest getting at least an extra gb of ram too - 2gb is defiantely going to be noticeable if you're playing all the new games...most recommend it now.

Hard drive is fine...bit small for this day and age, but will definately get you started

Sound card - defiantely upgrade...yours is very old, and you'll hear a big improvement in sound placement from the x-fi

Power supply - this is a tricky one...
never ever get a cheap power supply..it's just not done...a power supply has the ability to keep your computer runnign stable, or crash every 2 minutes. To make sure you've got enough power (which 400watts is going to be bare minimum) follow the PSU Calculator link in my signiture, and enter in all your computer details - this will give you what you need. Add 30% onto the wattage they suggest, and this is what you want for power spikes, and future upgrades.

then what supports my CPU?
what socket is it?

Hi fkyoungs, the cpu is fairly old now - released close to 2 years ago - same as mine...unfortuantely there's not alot of options for it...

Maybe 1 or 2 boards still..but they're not really worth it all that much.

I'd suggest save a bit longer, and get a new cpu too.

what kind of socket is my motherboard? A? 754? 939?
the Socket AM2 NVIDIA nForce 570 SLI MCP ATX AMD

All AM2 boards are socket 939, which is where the confusion sets in.

An Athlon X2 socket 939 will not work with an Athlon AM2 X2 socket 939.

The cpu can't talk to the ram correctly, so they won't work.
This is what i've been told, and how i understand it - however, I may be wrong.