Power, Heat, And Efficiency
Because efficiency is a ratio of work done to power used, its calculation begins with average performance.
In spite of the air-cooled card’s greater GPU speed, the Zotac GeForce GTX 285 Infinity’s higher memory speed takes the overall performance win.
A quick look at temperatures shows the excellent effectiveness of the stock-air cooling solution, at least when only one card is installed. The greatest problem with air-cooled cards is the airflow restriction that comes from packing multiple cards closely together, and that’s the problem Zotac solves with liquid cooling.
The air-cooled card adds one fan to the mix, resulting in higher idle power consumption. Builders must also consider the amount of power their liquid cooling systems consume, as numbers vary too much between systems to be considered here. Amazingly, overclocking at stock voltage has little effect on overall power use.
Bolstered by its good performance and lack of fan, Zotac’s GTX 285 Infinity takes the lead in energy efficiency. That efficiency lead will drop depending on how much power your liquid cooling system uses.