The Sapphire Radeon HD 7990 Atomic made its first appearance in June at this year’s Computex conference and features a pair of 28 nm “Tahiti XT2” GPUs, 6 GB of GDDR5 memory and six mini-DisplayPort outputs. Further information on the graphics card’s liquid cooling system and PCB design has now become available on Expreview.
In addition to the aforementioned two GPUs, the HD 7990 Atomic’s PCB features a PLX PLEX8747 PCI-Express 3.0 x48 bridge chip, an enormous 18-phase VRM that draws power from three 8-pin PCI-E power connectors, and provides each GPU with a 6+2+1 phase power supply (Vcc+VDDCI+MVDD).
According to TechPowerUp, the phases appear to have two 50A chokes per phase and driver-MOSFETs, while the ancillary phases use more conventional LFPAK MOSFETs, and most electricals on the 12-layer PCB are handled by Tantalum capacitors. As noted previously, the HD 7990 Atomic features a rather imposing liquid cooling system that includes a full-coverage block, a 120 x 240 mm radiator, a coolant reservoir and pump with coolant ports and a pair of 120 mm fans that spin at 1200 RPM.
The Sapphire Radeon HD 7990 Atomic is expected to be formally announced in a few weeks. At the time of writing, Sapphire hasn’t provided any information on its clock rates, pricing or availability.
