AMD Radeon HD 7950 Launch Review - PAGE 4

The "Tahiti Pro" is the second GPU released in the Southern Islands series, and like the Tahiti XT it is designed for extreme performance. Within the core AMD has packed roughly 4.31 billion transistors into a 28nm node with a die size of 365mm² . The core features 1792 streaming processors, 32 ROPS and 112 texture units. Along with the 800MHz clock speed, this gives the card a total compute power of 2.87 TFLOPs. Additionally, the HD 7950 has the same 384-bit, 3GB GDDR5 fame buffer that the HD 7970 has, with the only exception being the clock speed on this model is set at 1250MHz (5Gbps QDR) instead of 1375MHz (5.5Gbps QDR).

AMD has carried over the same physical attributes and stylings used on the HD 7970, so visually there is very little that separates this model from the HD 7970. This means the HD 7950 posses the same red and black color scheme and uses a rear mounted blower style fan. Along with the aesthetics, the HD 7950 also includes the same rounded design of the back end of the shroud, designed to improve ventilation when the graphics card is being used in CrossFireX configuration. As far as the dimensions go, the reference HD 7950 is actually the same length as the HD 7970, making it 10.5" long.

At the rear are two CrossFireX connectors and a PCIe Generation 3.0 x16 lane.  By using the PCIe 3.0 interface, the board has double the maximum data rate over Gen 2.0, giving the card up to 32 GB/s of bi-directional bandwidth on an x16 connector. It is going to be hard for a single graphics card to saturate the PCIe Gen 3 interface with so much bandwidth, so the benefit will most likely only be noticeable with scaling multiple graphics cards together in CrossFireX configuration.

Like the 6900 series, the HD 7950 comes equipped with PowerTune technology. PowerTune is basically a power management system that maximizes the performance of the board via dynamic power adjustment. It does this by increasing the GPU clock speed in real time when the GPU detects power headroom, and throttling the clocks when a certain power limit is exceeded. This allows the board to adjust the clock speeds on a microsecond level. The maximum PowerTune rating for the HD 7950 is around 200W at load. Since this is less than the HD 7970, the HD 7950 swaps out the 8+6 pin power configuration for just two 6-pin connectors.

The HD 7950 also supports "Zero Core Power". Traditionally, anyone using multiple GPUs in a single system had to deal with a high power idle state, simply because each card was still actively drawing system power; each graphics card could produce 30+ watts of power even when the system wasn't under load. With "Zero Core Power", the extra graphics cards in a CrossFireX system are disabled, shutting down the fans and capping any voltage from going to the core. Since PowerTune works on a microsecond level, "Zero Core Power" will not interfere with gaming as all the GPUs can become active again in just microseconds.

The HD 7950 uses the same video output configuration was saw on the HD 7970. In total there are two Mini-DP connectors, a single HDMI 1.4a connector and a Dual-Link DVI connector. The HD 7950 also uses the same non-stacked DVI design as the HD 7970, which improves both the acoustics and exhaust rate giving the air a clearer path to travel out of the heatsink. Also, again just like the HD 7970, the HD 7950 will come bundled with a HDMI to DVI dongle, and mini-DP to DVI dongle that allow the card to support up to three DVI connections out of the box.

With the AMD HD 7950 AMD is continuing their robust support for multiple displays. In all they have included a HDMI port that uses the latest 1.2 standard which allows them to support up to three monitors per port (via MST Hub) as well as AMD's HD3D technology. The middle HDMI 1.4a connector also supports 3GHz speeds with frame packing. Essentially this allows the connection to run the frames faster, which is going to make viewing images and playing games smoother across the board. The HDMI and DP ports can also be paired together to support HD3D Surround.