Anyone's free to use whatever build he or she wants. Everyone has to accept the forum rules, however, which means that builds below 4.0 are not supported on the forums, and custom builds are only supported as far as the providers (like ED2 above) want to support them (i.e. ED2 is the only one able to support you with his builds, the rest of the forum will not). 3.5-xxx builds (even those built by ED2) are full of crappy bugs (some of them game-breaking), so it's not a panacea for all users' problems (or even most users' problems).
And disabling Fog emulation really shouldn't give a speed boost. If you think it does, it's probably a placebo.
And disabling Fog emulation really shouldn't give a speed boost. If you think it does, it's probably a placebo.