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Leadtek WinFast PX6800 GT TDH Graphics Card: Overclocker's Dream (page 3)

Category: Video

by Alexey Stepin

[ 07/26/2005 | 04:14 PM ]

PCB Design

The Leadtek WinFast PX6800 GT TDH outwardly resembles another graphics card from the same manufacturer. We mean the WinFast A400 Ultra TDH that has a similar cooling system (for details see our article called Leadtek WinFast A400 Ultra TDH Graphics Card Review ).

There is the same massive copper heatsink under a casing of black translucent plastic. The new cooler is slightly different, though. For example, the fan used to be surrounded with a pressed-out rather than mesh grid. The fan itself is different and there’s now an additional aluminum heatsink under it.

These changes were intended to improve the cooling efficiency: the heat from the GPU die is now transferred not only via the heat pipe connected to the side ribbing, but also through the aluminum heatsink installed right under the fan. The geometry of the fan’s blades was changed and its main air stream now goes downward rather than sideways as it was with the WinFast A400 Ultra. So, the air stream first cools the aluminum sections and then splits up to cool the right and left copper sections of the heatsink the U-shaped heat pipe is attached to. Part of the air stream, like in the earlier version of the cooler, is driven through the casing to the reverse side of the card where a massive copper heatsink is located. This reverse heatsink doesn’t get much air, of course, but the small amount it receives is anyway quite enough.

Very thick gray-colored paste acts as a thermal interface between the GPU die and the cooler’s sole. The memory chips are interfaced through ordinary silicone paste. The rear heatsink contacts the PCB via soft pads of heat-conducting material. The whole cooling system is fastened on four threaded poles with spring-loaded nuts, and with two ordinary plastic clips. This ensures a robust fastening. The cooling system occupies two slots, so the card’s bracket is dual-slot, too.

The heatsink on the power circuit elements is made of copper and has elongated ribs. Otherwise, this graphics card doesn’t differ from the reference GeForce 6800 GT/Ultra.

Our sample of the WinFast PX6800 GT doesn’t support the video-in/video-out functionality, so the appropriate chip is missing on board. The 2.0ns chips of GDDR3 memory are manufactured by Samsung. Such chips are installed on an overwhelming majority of modern high-performance graphics cards, and this model isn’t an exception.

The frequencies of the GPU and memory are the GeForce 6800 GT’s standard 350MHz GPU and 500 (1000DDR) MHz memory.