MSI R4890 Cyclone OC

The MSI R4890 Cyclone OC has an unusual appearance, too. Although colored the traditional red, this card is simpler and, obviously, cheaper than AMD’s reference sample.

Unlike with the Sapphire Vapor-X HD 4890 2GB, the MSI’s power circuit can be described as 3+2 but the GPU voltage regulator is based on the same uP6206 controller from uPI Semiconductor. The memory voltage regulator seems to be based on two uP6101 chips.

Power is provided to the card via two 6-pin PCIe 1.0 connectors. This should be more than enough considering the modest power draw of an RV790, even overclocked.

The MSI R4890 Cyclone OC comes with a standard 1 gigabyte of graphics memory. All the eight Qimonda IDGV1G-05A1F1C-40X chips (1Gb, 32Mb x 32) can be found on the front side of the PCB. The same chips are installed on the reference Radeon HD 4890. As opposed to Sapphire, the MSI card’s memory frequency is not pre-overclocked and equals a standard 975 (3900) MHz.

And like Sapphire, MSI did not lift the core frequency of its card to the Radeon HD 4890 OC specs. The R4890 Cyclone OC has a GPU frequency of 880MHz. This is somewhat higher than that of the Sapphire Vapor-X HD 4890 2GB, but the difference can hardly matter in practical applications. The core has the maximum configuration possible for the RV790 chip: 10 execution SIMD cores (160 superscalar processors with 5 ALUs in each for a total of 800 ALUs), four texture processors (equivalent to 40 TMUs), and 16 raster back-ends.

The selection of connectors is nonstandard like with the Sapphire card, but the infrequently used DisplayPort is missing here. There are vent slits in the top of the mounting bracket. The card supports CrossFireX.

Although not unique, the cooling system of the MSI R4890 Cyclone OC has nothing to do with AMD’s reference sample. The heat-exchanger directing contacting with the GPU die is connected with a round heatsink with split ribs similar to the one of the Sapphire Vapor-X HD 4890 2GB. There is an 80mm fan on the heatsink. To the left and right of the fan there are semicircular heatsinks each of which is connected to the heat-exchanger with two thick heat pipes. The frameless fan is blowing downwards and sideways, cooling all these heatsinks.

The other components that might get hot such as memory chips and power transistors are cooled by the air flow created by the fan. There are no additional heatsinks on them. This cooling system resembles Zalman’s VF900 series solutions but is superior to them in the heat dissipation area and the number of heat pipes. Moreover, the pipes have a larger diameter of 8 millimeters as opposed to the conventional diameter of 6 millimeters and this should deliver efficient cooling at low noise. We’ll check this out soon.