This PowerColor Devil 13 HD 7990 isn’t a stock card by any measure, neither in size, ability, nor cost. In terms of specifications, the specifications seem to follow similar specifications as its regular 7970 brethren, with a 925MHz core and 1375MHz memory at stock settings, as shown in the screenshot below:
However, the card also has a little trick up its sleeve, with a small push button on the rear of the card that gives it an instant boost by switching to a new BIOS. Think of it as a “Turbo Boost” since it primarily increases the clock speed to 1 GHz, shown below.
If the clock speeds can be boosted with the press of a button, why bother keeping it at stock? You’re essentially getting an overclocked card, but that does come at a cost of slightly higher temperatures and noise levels for the fans to keep the card reasonably cool. So run it at stock for lower noise and temperatures, then push the red button to go Turbo when you want to game. Simple.