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Power Consumption, Temperature, Noise, Overclocking

Since Gigabyte Radeon HD 5870 SO uses a nonstandard PCB and works at pre-overclocked frequencies, we measured its power consumption on our standard testbed:

  • Intel Core 2 Quad Q6600 CPU (3GHz, 1333 MHz FSB x 9, LGA775)
  • DFI LANParty UT ICFX3200-T2R/G mainboard (ATI CrossFire Xpress 3200 chipset)
  • PC2-1066 SDRAM (2x2 GB, 1066MHz)
  • Enermax Liberty ELT620AWT PSU (620W)
  • Microsoft Windows 7 Ultimate 7 64-bit
  • CyberLink PowerDVD 9 Ultra/"Serenity" BD (1080p VC-1, 20 Mbit)
  • Crysis Warhead
  • OCCT Perestroika 3.1.0

The new testbed for measuring electric characteristics of graphics cards uses a card designed by one of our engineers, Oleg Artamonov, and described in his article called PC Power Consumption: How Many Watts Do We Need?. This device facilitates and automates the measurement process. As usual, we used the following benchmarks to load the graphics accelerators:

  • CyberLink PowerDVD 9: FullScreen, hardware acceleration enabled
  • Crysis Warhead: 1600x1200, FSAA 4x, DirectX 10/Enthusiast, "frost" map
  • OCCT Perestroika GPU: 1600x1200, FullScreen, Shader Complexity 8

Except for the maximum load simulation with OCCT, we measured power consumption in each mode for 60 seconds. We limit the run time of OCCT: GPU to 10 seconds to avoid overloading the graphics card's power circuitry. Here is what we managed to obtain using this testing methodology:

The Gigabyte card is not as economical as the reference Radeon HD 5870 in the desktop and video playback mode due to its factory overclocking. The GPU clock rate is not lower than 680 MHz even in 2D applications, which is a peculiarity of this version of Radeon HD 5870. Besides, the card refused to run OCCT:GPU for more than a few seconds. It would hang up and produce various visual artifacts, although was perfectly stable in games. This may be some kind of protection against severe synthetic tests such as OCCT or FurMark.

The cards from AMD and Gigabyte differ somewhat in terms of load distribution among the different power lines as they have different power subsystems. The Gigabyte Radeon HD 5870 SO loads the +3.3V line less but has higher load on the first +12V connector.

It must be noted that the voltage regulator design implemented by Gigabyte engineers is more efficient than the reference one in 3D applications. Notwithstanding the factory overclocking, the card’s peak power draw is but slightly higher than that of the reference sample. The results of the multi-GPU subsystems are approximations calculated by adding up the power consumption of their constituents in 3D mode. It is clear that the three AMD RV870 processors are going to be more economical than the pair of Nvidia GF100 chips. This naturally comes out of the difference in the number of transistors in these chips.

The cooling system of the Gigabyte Radeon HD 5870 SO performs excellently, keeping the GPU as cool as 60°C under load. No reference cooler from AMD or Nvidia can match that result even at a lower GPU frequency. Most importantly, the described product is rather compact as opposed, for example, to the Zotac GeForce GTX 480 AMP! which has a dual-slot form-factor. You must only make sure that no expansion card blocks the cooler’s left fan and prevents it from delivering its full performance.

And what about noise? Well, the fans of the Gigabyte Radeon HD 5870 SO rotate at about 2800 RPM in 3D applications and are perfectly audible. Fortunately, the spectrum of this noise is rather agreeable to the ear and does not irritate. It is a soft hiss of the air. The problem is that the fans do not slow down in 2D applications. This is the tradeoff for the GPU temperature of 39°C in 2D mode. Well, we could hardly expect an enthusiast-targeted graphics card to be completely silent.

For all its positioning, the graphics card didn’t do well in our overclockability tests. At its default GPU voltage it would hang the system up even at a GPU frequency of 960 MHz. Yes, the Gigabyte OC Guru tool offers flexible options for controlling the GPU and memory voltages but we didn’t risk using them. Volt-modding, both software and hardware based, often leads to an untimely death of the graphics card. The Gigabyte Radeon HD 5870 SO is superior in frequencies to the reference card anyway and we already investigated the overclockability of the RV870 core in our earlier reviews. So, let’s focus on the subject of this one as we are going to benchmark a 3-way CrossFire configuration. Our Gigabyte Radeon HD 5870 SO works with a Radeon HD 5970 without any problems. Let’s see what performance they deliver.

 
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