Installed the Accelero S1 w\ turbo kit on my Radeon 4890 before even popping it in the computer. Posting pics of temps
Before I post, I can say the reason that the idle power ratings are so low, seem because instead of down-clocking to 500mhz, like the 4870, this sucker downclocks all the way down to 240mhz
This sucker, runs very cool idle compared to my 4870, with the Accelero S1, the 4870 would idle around 45c, and load around 55-56c, now while that is VERY low compared to people getting 85-90c temps on the 4870, it's still impressive that the 4890 idles lower than the 4870, with the exact same aftermarket cooler.
One thing to note, as that on the Sapphire card I bought, it seems to have one very loud capiactor, I know this was a problem on numerous 4870x2s, and dosen't seem to impact performance, but I think I should state it. And this also, isn't a "custom" sapphire card, all current cards are the default ATI layout\design, so I'm guessing quite a few people will have the capicator sound, most it won't bother though, but I had to move my sound card away from my 4890 to get rid of interference