DDR3 seems the way to go but what is up with the 1066, 1333 and 1600MHz numbers.
What are the numbers that look like slot machine results....CAS7-7-7-20 to CAS10-10-10-20.
Is the most highest limit of memory on a 32 bit machine 4g or 6g? And if so what happens if you put in more? Is it ignored?
Highest limit on a 32 bit is 4GB. You can put in 4GB as that is usually 2 2GB sticks. 32 bit operating systems will usually report 3GB, but that’s another topic. Anything more the OS simply ignores it. You’re only wasting money and not hurting anything.
That 1066, 1333, and 1600 are the memory bus speeds. Your chip will tell you which one you need. Most chips will also allow you to use a lower memory speed but that results in less performance. My chip wants 1333MHz. Half of that is 667Mhz. So, I need memory rated at 667MHz. That is a little confusing but the basic memory approach is that using two memory sticks, or two banks of memory within one stick, the memory is interleave such that the first memory request comes from one stick and the next comes from the other, so the required speed of the memory stick is half of what your processor runs at. Memory is sold in stores as 1333 memory, but sometimes is stated as 667MHz memory. It is all in the packaging by the manufacturer, so look for both numbers and see what the packaging says.
The CAS numbers are timing numbers, and you shouldn’t need to ever look at those, unless you are doing some serious overclocking and actually know what you are doing and the vast majority doing that don’t.
Since this is your first build, I assume you won’t be over clocking, so go with the 1600MHz.
The other numbers are CAS latency and timing. Once again, not a concern.
If you are going with XP 32-bit, no need to buy more than 4 meg.
The processor you are looking at uses dual channel, so you’ll want to buy a pair of sticks, i.e. two 2meg sticks.