Gigabyte GV-R489OC-1GD

Unlike Sapphire and MSI’s engineers, Gigabyte’s developers took it easy and borrowed the PCB design of their GV-R489OC-1GD from AMD. The only external difference is the color of the solder mask and the configuration of interface connectors, but Gigabyte’s PCB has one important internal difference: its metallization layers are a double width. This technology is meant to improve the PCB’s ability to dissipate heat and is referred to as “2oz Copper PCB”.

The power circuit, borrowed from AMD’s reference sample is the most powerful among the versions of Radeon HD 4890 presented in this review. Following a 5+2 design, it consists of a 5-phase GPU voltage regulator and a 2-phase memory voltage regulator. The power circuit is controlled by two Volterra VT1165MF chips which support software-based adjustment of GPU and memory voltage.

Like in the original ATI Radeon HD 4890, a pair of 6-pin PCIe 1.0 connectors is used for power supply, but there is a seat for an 8-pin PCIe 2.0 connector with two additional pins.

Gigabyte uses the same GDDR5 memory chips as MSI: Qimonda IDGV1G-05A1F1C-40X. These 1Gb (32Mb x 32) chips are rated for a frequency of 1000 (4000) MHz. The manufacturer says that specially selected chips are installed on Ultra Durable VGA series products that guarantee high overclockability, but like MSI, Gigabyte does not pre-overclock the memory. Its frequency is the same as that of the reference card, i.e. 975 (3900) MHz.

The GPU frequency of 900MHz is the highest among the three cards and equals that of the Radeon HD 4890 OC. Like on the previous models, this card’s GPU works in its maximum configuration with 160 superscalar shader processors with five ALUs in each, four texture processors equivalent to 40 TMUs, and 16 raster back-ends.

The card has an original set of connectors that is different from the reference card’s as well as from the MSI and Sapphire models’. There is no dedicated D-Sub/VGA port on the Gigabyte card’s mounting bracket but there is one DVI-I, one HDMI and one DisplayPort. The HDMI connector is gold-plated but as we’ve noted above this has no effect on the quality of digital signal transferred through it regardless of the marketing claims of the manufacturers.

Gigabyte has equipped its GV-R489OC-1GD with a simplified version of Zalman’s VF1000 cooler called VF1050. We described it in an earlier review. The cooler is a large aluminum heatsink connected with four heat pipes to a heat-exchanger. It’s simple but effective thanks to the large heat dissipation area and should cope with the RV790. As opposed to the MSI R4890 Cyclone OC and Sapphire Vapor-X HD 4890 2GB, the fan has a 2-pin connection. It can be controlled neither automatically nor from Catalyst Control Center. The memory chips have no heatsinks and are cooled by the airflow from the fan. The power packs of the voltage regulators are equipped with a rather large heatsink. This cooling solution did well on the GeForce GTS 250. Now we will see how good it is with the Radeon HD 4890.