How to Silence a Radeon HD 4870 or 4890

Introduction

At the time we are writing those lines, the most powerful graphic cards available from Apple for the Mac Pro is the Radeon HD 4870. As we reported it earlier, we have successfully installed in a Mac Pro 2008 a Radeon HD 4890 PC card without flashing it. Those 2 cards, physically identical have the same problem: huge heat release when fully loaded which quickly translates into noise. This is a bit annoying when one enjoy everyday the sound of silence from the Mac Pro independently of the CPU load. As soon as a 3D demanding application is launched, or a GPU-optimized Pro application, the fan of the Radeon HD 4870 starts spinning at a more than noticeable level. So, the goal of the current article is to change the cooling system of the card to make it as silent as possible. 

The best heatsink currently available, associating performance and silence, is the Scythe Musashi.

We unfortunately could not use it because its fixation system in the back of the card is too long and would have prevent us to install the modified card in the lower PCI-Express slot in the Mac Pro. We should have then used a PCI-Express 8x, while blocking three additional PCI-Express slots. So, we decided to adopt the Artic Cooling Accelero Twin Turbo.

There is no issue for installing it on the Radeon HD 4870, and it has already demonstrated its efficiency in the past. We have a bit modified the default procedure for adapting this heatsink to the Radeon and in particular to the voltage regulators as they are especially subjected to high load on those cards and consequently warm up substantially. We will provide the procedure in details for a Radeon HD 4890, but it would be identical for a 4870 or any other card following the ATI/AM design (as all cards available from Apple).