Here is a quick job to bring down temps/noise on an HD4850
I have picked most of this up from various other jobs completed by other folks from the webnet.
I firstly checked GPU-Z for idle temps which were around 79c
I stripped the card from its stock cooling and cleaned the PWMs, GPU and
RAM and Vregs with IPA
The silver sinks came with the S1, however there were not eneough to cover the back end of the card.
So i used some low profile zalman jobbies, i replaced their themal tape with sekisui stuff recomended by clunk, they stuck well and the AC sinks had something similar on them so i didnt replace their tape.
One thing to note is the memory module closest to the right heat pipe needs to be low profile to ensure the S1 will fit.
Then i applied OCZ freeze to the GPU and mounted the S1 using just screws and washers.

The 120mm fan goes on with the zip ties that came with my new
PSU.
This quick job brought idle temps down from 79c to a much more pleasant 35c.
I will add some pics of this in the case when i get the cables sorted, i will also show some results with this card after some clocking next week after i get my new CPU.