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PCB Design

The representative of the third generation of Nvidia’s dual-processor graphics cards bears a striking resemblance to the second-generation GeForce 9800 GX2 in exterior and engineering solutions.

But while it was quite possible to do with only one PCB for the GeForce 9800 GX2 (and ATI indeed employed one PCB for its dual-GPU solutions), the GeForce GTX 295 just wouldn’t fit into one PCB. It would not be possible to accommodate two huge G200b chips and wire two 448-bit memory buses without making the PCB much longer, but 27 centimeters is already the maximum allowable length for most of today’s ATX system cases. Thus, the dual-PCB design is a must here rather than an engineering choice. Nvidia may create a simpler and cheaper design for dual-GPU graphics cards in the future when it transitions to GDDR5 memory.

Like on the GeForce 9800 GX2, the PCBs of the GeForce GTX 295 face each other and share a common cooler. This solution is questionable because the G200 chip is hot even in its 55nm version and the components of the two PCBs will heat each other up through the common heatsink. But as we said above, this component layout is the only way of creating a dual-GPU G200-based card within the existing height/length constraints. It is good that the card’s mounting bracket is not overcrowded with connectors as was the case with the GeForce 9800 GX2. There are a lot of slits at the top of the bracket for exhausting the hot air out of the system case. Some of the air is thrown into the system case, though.

As opposed to the GeForce 9800 GX2, it is not hard to take a GeForce GTX 295 apart. You have to remove the protective casing, unfasten the mounting bracket and all the screws that secure the PCBs on the cooler (the cooler is in fact the foundation of the whole arrangement). Then, you can carefully separate the thing into its parts, overcoming the resistance of the thermal grease.

 

 

The high component density of both PCBs agrees with our point that a single-PCB version of GeForce GTX 295 is impossible, even though there is a figured cutout in each PCB for air intake. The PCBs communicate through two flexible cables connecting the headers located in the left part of each PCB.

 
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