XFX & Sapphire HD 7950 3GB Reviewccokeman - January 30, 2012
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Much like the XFX HD 7970 Black Edition Double Dissipation, the HD 7950 BEDD uses a pair of axial fans to drive airflow through the heat sink to cool both the GPU core, memory, and PCB using XFX's Ghost Technology. The shroud is open at the top and bottom of the card to promote airflow through the Hydrocell Vapor Chamber heat sink. The top end of the card has a bright red anodized strip that highlights the name of the card and the technologies employed by XFX. The back side of the black PCB is devoid of any memory modules and the power circuit is highlighted in gold. Built on the 28nm process the HD 7950 features 1792 cores and 3GB of GDDR5 memory running through a 384-bit bus. XFX improves the build quality over the reference cards with its Duratec or C-Factor features that include solid capacitors, Ferrite core chokes, 2oz copper PCB and IP-5X dust-free fans.
The connectivity options for the HD 7950 include a single DL DVI, two Mini DisplayPort 1.2 connections, and an HDMI port that supports the HDMI 1.4a standard. DisplayPort 1.2 supports the use of an MST hub or daisy-chaining Displayport monitors into an Eyefinity configuration of up to six monitors. With Eyefinity 2.0, there is also added functionality of independent audio streams for each video stream, so that the audio streams follow the video to each specific monitor. The back end of the card does not have any real features save the end of the shroud. By reducing the amount of DVI connections on the 7900 series the airflow through the bracket is increased allowing for enhanced cooling.
Crossfire is supported by the HD 7950 Black Edition Double Dissipation from XFX in configurations of up to four cards. One thing missing from the HD 7950 BEDD is the dual BIOS switch seen on the HD 7950 and the Sapphire HD 7950 OC. Dual 6-pin power connections are required for this card, providing an additional 150 watts to the card in addition to the 75w from the PCIe slot. XFX recommends a 650 watt power supply to supply enough juice to run this card.
XFX uses a large Hydrocell Vapor-chamber based cooling solution to remove the thermal load from the 28nm core and 3GB of GDDR5 memory. XFX uses a PCB with 2oz copper layers to help dissipate heat through the card as well as through the heat sink. A pair of PWM-controlled 90mm fans are used to provide the airflow over the card. The airflow discharges both out of the top and bottom of the shroud and out of the mounting bracket. The majority of the thermal load is discharged back into the chassis with this kind of design. This design is said to be worth a 13 Celsius reduction in operating temperatures.
The HD 7950 is based off of AMD's Southern islands 28nm GCN architecture. Changes from the HD 7970 are minimal with a reduction in the shader cores to 1792, a drop in the texture units to 112, and changes to the clock speeds. Raster units are unchanged at 32 while the memory for the cards can be either 1.5GB or 3GB as on the XFX HD 7950 Black Edition Double Dissipation. Clock speeds on the core come in at 900MHz on the 28nm core and 1375Mhz on the 3GB of GDDR5 memory. The 28nm core is surrounded by a shim to protect the core from damage. The 3GB of GDDR5 memory is from Hynix and is part number H5GQ2H24MFR-T2C rated for operation at 1250Mhz. XFX uses GPU Edging to bin the GPU cores to find the highest clocking cores to ensure the Black Edition is a product with a difference besides the custom cooling and higher base clock speeds.
Like the HD 7970 BEDD the the HD 7950 Black Edition offers an upside right out of the box with higher clock speeds on the core and memory. Custom Hydrocell Vapor Chamber cooling and Duratec construction all offer long term value.