So I think it's safe to say the reference cooler is not so great.
On the bright side, under load it has lower power draw than a 4830 according to the charts, so I should hope you could run an Accelero S1 r2 either passive or with low volted fan on it. I'm currently shopping for my first new video card in 3 years and it seems like every stock video card is deficient in one way or another. Either the stock cooler is too loud, the whole card is way overpriced, or it has a crappy passive cooler that doesn't provide enough cooling. My plan at this point is to just get whatever the most affordable 9800GT is and put an S1 on it.