Gigabyte's 7970 SOC in Detail
Along with the upgrades we just mentioned, Gigabyte has outfitted the card with a massive heatsink that occupies three expansion slots, forcing the fans to be mounted on the side rather than on top to avoid blocking a fourth slot. The heatsink measures 20cm long, 9cm wide and a staggering 4.5cm tall. When you include the vapor chamber and nine copper 6mm heatpipes, the card weighs a whopping 3.5lbs (1.6kg).
The downside to this setup is that Gigabyte had to use five small 40mm high-speed fans to circulate air over the enormous heatsink (this is marketed as its "WindForce 5X" design). These fans are configured to suck air through the heatsink using a pull rather than push system, which Gigabyte says is much more efficient for this design.
The company also claims that despite using five tiny fans, its design is much cooler and quieter than AMD's reference. Surprisingly, at 10,000RPM the fans are said to generate just 53dBA of combined noise, while the single 80mm reference blower generates 62.2dBA at 5100RPM.
With overclocking being the sole purpose of this card, Gigabyte gets things started with some factory increases. The GPU has been bumped from 925MHz to 1080MHz -- a decent boost, though we think it should ship at a minimum of 1.1GHz.
Perhaps more disappointing is the fact that the memory has been left alone at 5500MHz, so we don't expect to see a huge difference between the HD 7970 SOC and the GHz Edition without some manual overclocking. Further aiding that effort is a pair of 8-pin power connectors, upgraded from the standard 6-pin/8-pin configuration.
Gigabyte has also equipped the HD 7970 SOC with another unique feature called "Extreme Dual BIOS," which lets you toggle between your primary and secondary BIOS with the press of a button.
Extreme Dual BIOS contains two different BIOS chips designed for separate purposes. The standard (Blue) BIOS is for air-overclocking, while the secondary (Red) BIOS is intended for LN2 overclocking and is designed to avoid potential cold bug issues at extremely low temperatures.
Connectivity is one area in which the HD 7970 isn't so extreme, featuring the standard configuration of two Mini DisplayPorts, an HDMI port and a Dual Link DVI-I connector.