Hi there. First thing (just to clear this up so there isn't any confusion), you need to know both this and the official abit forums are user-to-user help, not official abit support. To speak with an abit employee, you have to call or email them. So it's not OUR boar per se; we may just own one.

Now, moving on, here are some answers that will hopefully help you, in the order they were asked:
  • The NB-FID works just fine with my Phenom 9500. I have a feeling you still have Cool N' Quiet enabled. Once you disable that, you should see the option to change your multiplier.
  • Most likely the reason you can't OC your memory is the tRFC timing. That timing on this board is measured in ns and are selectable individually for all four DIMMs. By default, the empty slots are set to 75ns. Unfortunately, for whatever reason, it'll change one populated slot to the setting it should be at (either 105ns or 127.5ns, depending on your memory) but it treats all three other DIMMs as empty with respect to that timing. Anyway, long story short, change the DIMMs that you have memory in to 105ns and try again. You can probably clock your memory higher at that point. If not, try changing both of them to 127.5ns.
  • No idea which BIOS is 'best' for a 9850, but I use v.13beta02 with no issues what-so-ever. If I had a 9850, this is the version I'd be using.
  • Sorry, never used Vista (and don't plan on it), so I can't help you with the administrator question.
  • Likewise, I have no clue whether the PWM can handle a 200W power draw. The 9850 is 125W though...what do you plan on doing to make the board need 200W output?