HD6990 PCB top
Here we can see the card fully exposed and stripped of it its cooling. While the cores are framed by the memory modules in symmetry, the PCI Express bridge chip is slightly off centre to make way for the power regulators. Overall, the PCB is of very good quality with precise soldering throughout as you would expect.
HD6990 PCB rear
The rear of the card has the remaining 2GB of Hynix GDDR5 along with two voltage regulators, one for each core.
Power regulation
Here's a close up shot of one of the Volterra VT1556MF PWM programmable regulators. Each core has one of these chips and is the staple controller for the 6900 family. Offering 12C communication and control, it provides all of the high level voltage regulation.
PCI-Express Bridge chip
The PCI-Express bridge chip is the same specification of the HD5970 which is also manufactured by PLX but still has the old ATI insignia, possibly because the chip is from the parts bin of previous graphics cards. This bridge chip is fully compliant with PCIe 2.1 x16 specification so can provide enough bandwidth per core regardless of the strain they are under.
Power inductors
Power delivery to the two Caymen XT cores comes courtesy of 8 ICs (4 phase to each core) hidden beneath the white stickered inductor shields. The memory modules get provided with 2 phase power circuitry while the PCI-Express bridge chip makes do with a single phase.
MOSFETs
The power from the inductors are then filtered by Cooper Bussmann chokes (above) who are one of the oldest, leading players in the power circuitry market having over 90 years experience in the business so you can be assured of quality.
Cayman XT core
Above is a shot of the Cayman core itself. Based on 40nm architecture, the core yields over 2.64 billion transistors on a die of just 389 mm². Like all previous AMD/ATI cards, the core is fully exposed and aside from the aluminium frame, it has no protection from misaligned coolers so please be careful if you intend to remove the cooler yourself.
Memory modules
The HD69900 comes equipped with 16x256mb Hynix GDDR5 modules totaling 4GB. The chips identification is H5GQ2H24MFR-T2C signifying that they are rated to 1250MHz (5000Mhz effective) when provided with 1.5v. It remains to be seen if this speed can be exceeded then as the AUSUM switch increases memory bandwidth to 5.5 GB/s.
With the technical furore out of the way, let's now take a look at the bundled software of the ASUS HD6990...
