I have AMD Opteron 146 at 2.7ghz, 1gb OCZ ram and my pc handles premier elements no problems and I usually have edits that are between 2 minutes - 1hr or so long.
According to
this, AMD added SSE2 with the Opteron, which is what you have. I have an AMD Athol XP 3000, bought sometime in 2004.
Interesting though - means Adobe are being economical with the truth in specifying Intel only. I wonder what the deal is?