I have a bit mixed feelings about the Sapphire HD 4850 Toxic. The inclusion of the Zalman VF900 cooler is a great choice, but the fixed fan speed is not. Since the fan is always running at the same speed of around 1700 RPM, it will obviously lower the idle temperatures a great deal. But this also results in a very noisy card in idle. Under load the temperatures are considerably lower than on the HD 4850 reference design, but the card is still louder as well. Sapphire's higher clock speeds give the card a healthy performance boost of about 5%, but still 12% slower than the reference HD 4870.
A big issue is the price though, with all the recent AMD price drops the reference design Sapphire HD 4850 is going for $170 or lower, the Toxic variant costs $40 more - the retail price of the Zalman VF900. So the price increase seems to be justified, but whether you can justify that amount of money is up to you to decide. Still, it is great to see Sapphire release innovative products that give additional choices to the customer.