goates,
With nForce you have to be very careful with RAM. That Chipset is very picky about RAM.
When it comes to RAM, your best option is two matched sticks of RAM, so in Std Speed's case he would want a pair of 512MB Sticks if he wants 1GB of RAM. You can do 2 sticks of 256Mb in the first two DIMMs which belong to the first Memory Controller and 1 512MB stick in the second Memory Controller to still get TwinBank but it is very tricky to get running smoothly. If you are going to buy RAM today, you want at least PC-3200 since all the new CPUs have gone to a 400Mhz FSB (200 DDR). Should you upgrade CPU and/or Mobo in the future, you will want RAM that you can use.
Take Care,
Richard