you sholud try to overclock you pc to multiper of 11 if possilbe.
But you want to keep your temp between 30 C and 40 C. The only problem with overclocking is that you will reduce you hardware life. But most part last about a million hours anysways so you should be fine.
64x is STABLE, it doesnt crash or anything, its just that a lot of programs that aren't as popular don't support the 64x system. it runs fine though, although i havnt noticed any speed increase over the 32x. if i vow never to use the 64x software again, could i justify downloading it? lol
edit: haha, if you have your fonts and sizes set to default, and your window is maximized on an 800x600 resolution or higher, all the "64x"'s in my reply line up (on IE anyway..)