XFX R7790 Black Edition Overclocked Reviewccokeman - April 18, 2013
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XFX R7790 Black Edition Overclocked Closer Look:
XFX R7790 Black Edition Overclocked is based on AMD's GCN 28nm Bonaire core sporting clock speeds of 1000MHz on the core and 1225MHz on the GDDR5 memory. From the front the R7790 BE looks just like its full sized counterpart, the XFX HD 7970 Black Edition, just well smaller at a hair under eight nches front to back. This version of the R7790 Black Edition uses XFX's own Double Dissipation cooling system featuring a pair of dust free fans to push air through the heat sink. On the back side are four of the eight GDDR5 memory ICs. XFX is using an in-house designed and built PCB for the R7790 Black Edition Overclocked that helps improve the reliability and power distribution to the highly binned core. This card is built for use in a 16x PCIe 3.0 slot with backwards compatibility. The top view of the card features a red stripe with the XFX logo, the series of the card (7700) and the technologies employed. A pair of heat pipes are visible looking through the shroud.
Display connectivity for this card from XFX includes a single HDMI 1.4a port supporting output protected high bit rate 7.1 channel surround sound over HDMI, a single full sized DisplayPort 1.2 port that supports resolutions up to 4K, a single DL-DVI port, and a single SL-DVI port. In this configuration the R7790 supports up to four independent displays up to a 16K x 16K resolution. The mounting bracket features the XFX logo that actually flows more air than the reference design for added cooling and visual appeal. The back end of the card is wide open as part of the Ghost Thermal design to allow airflow out of the shroud after cooling the PCB and onboard components.
Crossfire is supported on the R7790 BE by using a second HD 7790 video card in a motherboard that supports the use of the configuration. Only a two card configuration can be implemented due to the single Crossfire Bridge connection. Power needs for this card are by way of a single 6-pin PCIe connection on the back end of the R7790 BE. Situated here it makes cable routing a bit easier in the chassis.
The shroud is held in place by five screws and is easily removable to illustrate the Double Dissipation cooling solution. The dual heat pipe-equipped heat sink is held on by four spring loaded screws. XFX is using a custom PCB on this card in lieu of the reference design and is equipped with its Duratec professional grade components. The black color of the PCB is a deep black that stays that way even under a bright light; a much better look than on some video cards I have looked at.
XFX's Double Dissipation cooling solution consists of a pair of copper heat pipes that are soldered to a copper contact plate that carries the thermal load up to a large (for this card) aluminum fin array topped with a pair of 80mm dust free fans. The fans feature multiple seals to prevent dust intrusion into the fan's motor windings slowing it down and ultimately leading to failure; one possible cause for overheating and damaging the core. On this solution the fans are actually hard mounted to the heat sink rather than the fan shroud.
The heart of this card from XFX is the 28nm GCN Bonaire core from AMD. It is equipped with 2.08 billion transistors, 896 stream processors, 56 texture units, 16 ROPs, and 1GB of GDDR5 VRAM running through a 128-bit bus. Baseline clock speeds from AMD are 1GHz on the GPU core and 1500MHz on the GDDR5 memory. XFX bumps these up to 1075MHz on the core and 1600MHz on the 1GB frame buffer. Hynix memory ICs part number H5GQ1H24AFR-ROC rated for operation at 1500MHz are used. A binned core and high rated memory should provide some spirited overclocking.
So how does a custom PCB, a binned core, excellent memory ICs, and custom cooling impact performance? Long term solutions are the key here but let's see how it handles in the short term.