MSI HD 7970 Lightning "Reactor Core" Detailed
 

If you've seen the first pictures of MSI's Radeon HD 7970 Lightning graphics cards, you may have noticed an unusual-looking round cutout on its backplate, right behind the GPU. We are learning that this cutout, and the tiny headers on the exposed PCB are actually a socket for what MSI is referring to as a "Reactor Core" (I can imagine Iron Man fans prepping their flame throwers right about now).

The "Reactor Core" is a round add-on device that sits on this socket. It is essentially an add-on PCB that holds a battery of tantalum capacitors, which further conditions power for the GPU. Apart from capacitors, there are a few blue LEDs and a round, transparent window that make it light up. To what extant this gadget helps with maintaining stable OCs remains to be seen, but on the "flip-side", it could pose spacing issues with other add-on cards located right above HD 7970 Lightning cards that are outfitted with one of these.

http://www.techpowerup.com/161847/MS...-Detailed.html