The only thing that's causing instabilities is you overclocking it without fully understanding what it takes to keep the system stable. The multiplier only effects your clock speed, the Vcore is what effects stability and is also what causes more heat in addition to the extra clock speeds.. If you want to lower your multi to raise your FSB then you can do that, but if you keep the CPU and RAM at a 1:1 ratio then you're overclocking the RAM and your CPU will be underclocked until you get the HTT and the multiplier to equal more than the stock speed.
If it's 200x10 = 2GHz on stock and you lower your multi to 9, then you'd have to go all the way to 222x9 = 2GHz, so that's only effecting your memory.
Have you made sure to read the basics of overclocking at the top of the thread? You should really familiarize yourself with the basics before you start to jump into it.