Most desktop computers use non-ECC memory (unbuffered or unregistered) because its cheaper, faster, and because the amounts of data flowing through are small enough that errors seldom occur. When you have a server using large amounts of RAM, you want to use ECC memory because it has an extra buffer built in. It makes the memory slower (CL2 becomes CL3 as it says in your quote). Thats the Latency measure of the RAM. So it waits one extra cycle to "check" the data and make sure there are no errors. Using non-ECC RAM in a server with lots of memory is just begging for data errors.
A desktop computer isn't going to run appreciably faster (and may even be slower) with over 1GB of RAM to start with, so there's no reason to add more unless you have some applications that need it (at least so far as I understand). Also, using ECC memory in a desktop (unless required by the manufacturer of the motherboard) is going to slow you down.
Sandra is a great program, but every tip doesnt apply to you. Keep that in mind.
