Best cooler for HD4850

I have Asus HD4850, which gets extremely hot sometimes while playing games. Though it doesn't crash or something, to be on safer side, i am thinking to replace the stock fan with GPU cooler. I was reading article in computer magazine which states zalman vf900 is very good to put on HD4850. Its bit noisy but it will keep GPU temperature down. Another disadvantage is; pci slot next to it won't be available to use anymore which i am willing to sacrifice as i don't need it anyway.

Need your views about GPU cooler, any suggestions?

I have tried Rivatuner, but it doesn't support 4800 series. Also I have ASUS Smart Doctor with which i can monitor temperature and fan speed. Whats the highest safe temperature?

my card current temperature is 53C/127F

53C is fine. if you have the smart doctor utility, set your fan speed to 40% and leave it there and don't worry. your GPU won't have a problem, assuming you have decent case ventilation.

I have read much on 4850's since I bought one myself last month. I am no expert but the gpu should be safe for temps of 80c or even 90c. I have read the stock fan on the 4850's throttle between 14 and 24 percent. So one fix has been to write a custom fan profile in the gpu bios to speed it up. There are posts describing this and most feel that even a fixed speed of say 30 or 40 percent is a great improvement. GPU temps might drop from 90c to something around 70c under load. Of course, the con to this approach is an increase in noise db. My new build should arrive this week so i hope to sort it all out.

make sure that you can tolerate a VERY LARGE amount of noise before setting the fan to above 50-60%. I tried 70%, and it was around 2x-3x as loud as a 140mm (at 80 some CFM) and 3 120mm fans (88 CFM) all at max. Right now, when the card is under load, I put the fan speed to 40%, and the temp might hit 70C. As soon as load is gone, goes to about 45C.

Gfxchilla
http://www.ncixus.com/products/28504/KL-02/Coolink/