Now let's check out the card's cooling system and its efficiency. The key component of the reference cooler is the GPU heatsink.
It consists of five copper heat pipes, 6 millimeters in diameter, which are part of the cooler's base (the so-called direct touch technology). The pipes go through aluminum fins, about 0.35 millimeters thick and placed 1.5 millimeters apart. It must be noted that the heatsink's dissipation area is not really large. The pipes in the base are placed 1.5 millimeters apart from each other, too. The heatsink is all nickel-plated.
There is a thick layer of gray-colored thermal grease between the GPU and the cooler's base.
The amount and quality of thermal grease is highly important for coolers with direct-touch technology to show their best performance. More so than for coolers with a classic base. Running a little ahead, I can tell you that when I replaced the default thermal grease with a thin layer of Arctic Cooling MX-3, the peak GPU temperature lowered by 3°C. The temperature did not change in 2D applications, though.
The second component of the reference cooler installed on the GeForce GTX 480 is the metallic plate with a blower.
The plate has contact with the graphics memory chips and power circuit elements via thermal pads. The speed of the blower (whose maximum output power is 21 watts, by the way) is adjusted by the card automatically depending on the temperature. Interestingly, the blower's speed grows up smoothly but when the load is removed from the GPU, it plummets down suddenly. After the noise produced by the GeForce GTX 480 cooler at near-maximum speeds, you get an impression that the blower turns off altogether but that's not true. In 2D mode, when the card's clock rates are lowered, the blower is working at 44-46% of its full capacity. I will discuss the noise factor later on. Right now, let's check out the efficiency of the GeForce GTX 480's reference cooler.
The graphics card was loaded by the resource-consuming Firefly Forest test from the semi-synthetic 3DMark 2006 benchmark running at 2560x1600 with 16x anisotropic filtering. The GPU temperature and the blower's speed (in percent from its maximum) were monitored with MSI Afterburner version 1.5.1 which does not yet fully support the GeForce GTX 480 series. The ambient temperature was 25°C during this test. The graphics card was installed into a closed system case whose configuration is listed in the Testbed and Methods section. The card's default thermal interface was used.
So, let's see how hot the GeForce GTX 480 is when its blower works in the automatic mode as well as at the maximum speed.
The new graphics card is obviously very hot. Running the 3DMark 2006 test, its GPU quickly grew as hot as 95°C but then, thanks to the blower accelerating to 70-78% (about 3600 RPM), dropped to 91-92°C and did not change thereafter. If the blower's speed is manually set at its maximum speed (about 4780 RPM), the GPU temperature is no higher than 68°C. The performance of the heatsink depends greatly on the blower's speed, which indicates that its heat dissipation area is not large enough.
I also checked out the GeForce GTX 480's reference cooler with FurMark version 1.8.0 (with the EXE file renamed) which was running in full-screen mode at 2560x1600 with 16x anisotropic filtering enabled in the GeForce driver. When the blower was working in automatic mode, the picture was almost the same as in 3DMark 2006, except that the peak temperature was 98°C, but when the blower automatically accelerated to 4150 RPM, the temperature lowered to 91-92°C. And here are the results at the maximum speed of the blower:
The resulting GPU temperature is as high as 86°C. As you can see, the new graphics card is very hot and its cooling system is very noisy in 3D mode. This shouldn't come as a surprise, though. As a matter of fact, top-end products from both Nvidia and AMD/ATI have never been cool or quiet. Besides, there will surely appear alternative cooling solutions that can often be up to 30°C better than the reference samples while being incomparably quieter (I can recall the Arctic Cooling Accelero Xtreme GTX 280 or Thermalright's solutions). The only problem is that it does not feel good to spend $500 for a graphics card that requires you to change its default cooler with a better one (possibly losing your warranty). Well, perhaps we should wait for GeForce GTX 480 with alternative coolers to come out.
I measured the overclocking potential of my GeForce GTX 480 with EVGA Precision version 1.9.2.
Considering the temperature, I did not expect anything impressive from the new GPU at overclocking. Indeed, I could only increase its frequency by 45 MHz without losing stability or provoking image artifacts. The resulting frequency was 745 MHz (+6.4%). As opposed to the GPU, the 0.4-nanosecond memory chips did much better, being perfectly stable at 4780 MHz (+29.3%).
I am not absolutely sure that the memory test from the latest version of OCCT works correctly with the GeForce GTX 480, but it takes almost all of the graphics card's 1.5 gigabytes of memory to run.
The higher memory frequency did not affect the temperature of the graphics card's PCB and GPU.
Winding up this description, I want to give you a link to the graphics card's BIOS and remind you that the recommended price of the Nvidia GeForce GTX 480 is $499. The card is going to start selling worldwide on the 12th of April.