Difference between 3200 DDR and 3500???

What is the difference? Isn't 3200 400 MHz? Does that make 3500 433?

You are correct. PC3200 works up to 400MHz and PC3500 can work up to 437MHz. Basically people using for example the newer Pentium 4 processors (with the 800MHz FSB) need PC3500 memory if they plan overclocking their system. This is because at default settings, their CPU will run at 4x200=800MHz FSB and their memory at 2x200=400MHz. If they increase their bus speed to 215MHz for example then we have 4x215=860MHz FSB for the CPU, and 2x215=420MHz for the memory (note that the CPU and memory have to operate at the same speed, which is 215MHz in my example).

LOL! See? That's what happens when you are surfing the internet at 1am in the morning instead of sleeping