Cooling System and PCB Design
Despite our suppositions, the GeForce 7800 GT graphics adapter doesn’t use the same PCB as GeForce 7800 GTX is based on. The newcomer is based on a specifically designed PCB, which should probably boast lower production cost.
The graphics processor and graphics memory voltage regulator circuitry of the GeForce 7800 GT is much simpler than those of the GeForce 7800 GTX and GeForce 6800 Ultra. There are fewer electronic components involved than in case of the other two graphics solutions. Since the voltage regulator design is simpler and the load-bearing elements have been moved to the other side of the PCB, the board is overall shorter than the PCB of GeForce 7800 GTX, although it is not so compactly built as the solutions from ATI Technologies.
There are very few components onboard of GeForce 7800 GT, which may indicate that there is enough room for further price reduction.
The reference GeForce 7800 GT card uses 256Mbit GDDR memory chips from Infineon with 2.0ns access time. The nominal working frequency of this memory is 1000MHz. the graphics card can accommodate up to 16 memory chips, which allows using up to 512MB GDDR. Note that NVIDIA refused to equip its GeForce 7800 GT with 256MB of memory on both sides of the PCB to ensure better cooling of the memory chips: the not very high working frequency of the GDDR memory they use doesn’t require very powerful heat-spreaders.
The cooling system of GeForce 7800 GT has also changed compared with what we see on GeForce 7800 GTX. The cooler of the new GeForce 7800 GT is much more compact than the one used on GTX model, the fan is also smaller, and its rotation speed doesn’t change. From the conceptual point, the cooling system of NVIDIA GeForce 7800 GT inherited a lot from its predecessor: the chip cooling system is built with heatpipes, and the fan is installed in such a way that the chip heatsink could receive best cooling.
As for the additional features of GeForce 7800 GT, I would like to mention the VIVO controller – SAA7115HL from Philips, which was also installed on GeForce 7800 GTX. It looks like the video capturing features have become standard for all NVIDIA based high-end solutions.