PCB Design and Functionality
Once Gigabyte switched to black PCBs with black connectors, their products lost some of the exterior appeal and became a little less informative to the eye. Before you could easily grasp which memory slots belonged to which memory channel, which graphics card slots were the primary ones and which operated at lower speeds. Now you should better consult the manual, because black connectors are visually lost against the background of the dark PCB textolite and are hard to distinguish.
Just like on the top GA-990FXA-UD7 model, the processor voltage regulator circuitry on this one works as 8+2 and uses only highly-integrated components, where two MOSFETs and a control unit are combined into what is known as a single Driver MOSFET chip. Flagship AMD processors even in non-overclocked mode consume quite a bit of power that is why all voltage regulator components that tend to warm up a lot are topped with an additional heatsink. It is connected to a heatsink on the chipset
The expansion cards will go into PCI, PCI Express 2.0 x1 and five PCI Express 2.0 x16 slots. Although there are only three of these five slots are capable of supporting AMD CrossFireX or Nvidia SLI graphics card configurations. You can install one or two graphics cards that will be working at full speed, or three graphics cards, which will work as x16/x8/x8.The remaining two slots work as PCI-E x4, but they will be blocked if the graphics cards have large coolers. Besides 6 SATA 6 Gbps ports provided by the AMD SB950 South Bridge, the mainboard has two additional SATA 6 Gbps ports implemented using an additional Marvell 88SE9172 controller. A second controller like that provides support for eSATA and Power eSATA ports on the back panel.
The back panel on GA-990FXA-UD5 has the following ports and connectors on it:
- PS/2 connector for keyboard or mouse;
- Eight USB 2.0 ports, six more are laid out as three onboard pin-connectors;
- Optical S/PDIF and five analogue audio-jacks provided by eight-channel Realtek ALC889 audio codec;
- IEEE1394 (FireWire) port implemented via VIA VT6308P controller, the second port is available as onboard pin-connector;
- Two eSATA 6 Gbps ports implemented via Marvell 88SE9172 controller - one of them is Power eSATA (blue connector), another controller like that adds two internal SATA ports;
- Two USB 3.0 ports (blue connectors) implemented via EtronTech EJ168 controller, second controller like that provided an additional internal pin-connector for two more USB 3.0 ports;
- A local network port (network adapter is built around Gigabit Realtek RTL8111E network controller).
As for the unique peculiarities of Gigabyte GA-990FXA-UD5 mainboard, we should definitely mention two BIOS chips, a special USB ON/OFF Charge port that serves for charging mobile devices. As always they use very convenient color coding for the front panel ports and connectors. All connectors are marked not only on the textolite next to them, but also inside the actual connector. As for the drawbacks, I should say that the board has only four fan connectors, only two of which are four-pin ones and allow adjusting the fan rotation speed.
We summed up all the major mainboard specifications in the following table for your convenience: