Cooling

As for GTX 295/285, we have already described coolers of these reference cards here and here.

ASUS EAH4850 MATRIX (RADEON HD 4850) 512MB
This cooling system ejects hot air out of a system unit, when the turbine drives the air through the entire radiator. The cooler takes care of the core alone, memory chips come with their own small heatsinks.
ASUS EAH4870 MATRIX (RADEON HD 4870) 512MB
It's a similar architecture reinforced with the second fan. It's a little noisy despite the low fan speed.

We analyzed thermal conditions of each card using RivaTuner.

ASUS EAH4870 MATRIX (RADEON HD 4870) 512MB

ASUS EAH4850 MATRIX (RADEON HD 4850) 512MB

ASUS ENGTX285 Ultimate (GeForce GTX 285) 1024MB

All these cooling systems apparently cope with their responsibilities.