i'm a long time user of all windows, repair/builder, i did the tweaks all but system restore, on my 3.4 gigahertz running vista home, i saw a good performances increase.
on my 3.0 ghz 1.5 ram computer, i did the same tweaks, and can't really see much improvment. i also did the advanced harddrive tweak on the vista enterprise machine, don't see much diff there either.
i did the bandwidth tweak on my xp computer, and lost speed there. i 'm use att dsl, and normally run at 1.5 mbs per on downloads
with the tweak, only about 670, using the speed test from internet frog website.