AMD Radeon HD 6790 Review - PAGE 4

The Sapphire HD 6790 uses the same specifications as the reference model, which gives it a 840Mhz GPU clock speed and a total 1GB frame buffer clocked at 1050MHz (4.2Gb/sec effective) that runs on a 256-bit memory interface. However, where the Sapphire models differs from the reference model is in its custom PCB and fansink design.

The Sapphire HD 6790 uses a dual-slot fansink that has a centrally mounted 92mm intake fan that also has a large heatsink positioned under the fan. In addition, the Sapphire card also uses a sleek black heatsink shroud that has silver accents and a product sticker along the back.

AMD stated their reference design will not be seen on the market, and was merely a sample designed to show the raw gaming power of the HD 6790. Sapphire's model will be a better example of the type of cards we will see upon the release of the HD 6790, with each AIB partner using their own PCB, thermal solution and power connectors.

Under the heatsink shroud you can see the Sapphire model is sporting a rather robust cooling solution for a card in lower mid-range market. On top of this, the HD 6790 also has an additional cooling solution added to the front mounted VRM, which will keep the components cool even during prolong gaming periods. This can help improve the total power efficiently of the graphics card as well as increase its longevity.

On the PCB Sapphire has included eight ELPIDA branded memory chips that surround the Barts LE based graphics processor in an L shape. Additionally, the card uses a 4 + 1 phase unit design, but surprisingly Sapphire has used a iron core chokes are opposed to the ferrite core chokes used in higher-end cards. Still, the rest of the board design is excellent, as it includes all solid Japanese capacitors and has two 6-pin PCIe power connectors.

The thermal solution used on the Sapphire HD 6790 includes three copper heatpipes that extend from the base of the cooler into the aluminum fin array. This will allow the heat to transfer evenly throughout the array, but to improve the cooling even further Sapphire has included a solid copper base that makes direct contact with the GPU. Also, Sapphire has included a large 92mm fan that draws air in from under the graphics card and exhaust it throughout the heatsink. In all this is a very robust design, but since the heat is not directed out of the graphics card, most of the hot air will be dumped back into the case. However, since this is a lower mid-range graphics card we doubt the heat will be great enough to affect the temperature of the other components.