Cooling performance
Sapphire claims the Radeon HD 4870 X2 ATOMIC "brings workstation-class cooling to the PC", and though we wouldn't go as far as to call it workstation-class, it's certainly a whole lot cooler than AMD's reference HD 4870 X2.
We perform our testing on an open test-bed with a 120mm fan simulating case airflow. A direct GPU-temperature comparison between an ATOMIC-cooled and reference-cooled card is as clear as night and day.
| Graphics cards | Sapphire HD 4870 X2 ATOMIC | Sapphire HD 4870 X2 |
|---|---|---|
| Ambient temperature | 22°C | 24°C |
| Idle temperature | 37°C | 73°C |
| Load temperature | 64°C | 95°C |
| Ambient-to-load delta | 42°C | 71°C |
Cast your memory back a few pages and you'll recall ASETEK claiming its LCLC system can lower Radeon HD 4870 X2 temperatures by up to 28°C. Sapphire's implementation goes a step further and lowers load temperature by a substantial 31°C.
GPU cooling is impressive, and even more so when you consider that the same closed-loop system is taking care of CPU heat, too. Speaking of the CPU, how does the cooler perform in processor terms?
Sadly, not quite as well. At idle, we measured the temperature of our Intel Core 2 Extreme QX9650 processor at around 49°C. Putting it to work, we ran four instances of Prime95 and watched CPU temperature rise to 57°C - not dangerous by any means, but we'd hope for cooler when liquid-cooled.
It appears, then, that the closed-loop system strains to deal with the combined heat-load of both CPU and GPU. However, as an easy-to-install all-in-one unit, it offers perfectly adequate cooling that should lower overall system noise.
