HIS HD6990 4GB Graphics Card Review

👤by Sahil Mannick Comments 📅17-06-11
Closer Look

The graphics card

Rather than curvaceous lines of the GTX590, AMD and HIS in this case have settled for a no-nonsense box shaped design that is made appealing by its metallic finish and the blue Excalibur sticker. It is reminiscent of other reference cooled HD6990 but it still retains the sleek look we have grown accustomed to with AMD reference cards. The card is a hefty 30.5cm in length so buyers need to be wary before purchasing. The card’s most distinctive feature is its centred position fan, similar to Nvidia’s GTX590 despite the clear difference in fan design.

On its side

The sheer size is apparent when removed from the packaging. At 1kg in mass, puny is the last word you’d use to describe and thankfully this is all attributed to the cooling employed to tame the two beasts within.

The back of the card

At the back, the graphics card sports a 1.5mm thick metal back plate for additional cooling and to provide structural support when installed inside. The heatsinks are secured by x-shaped brackets and 4 spring loaded screws to ensure good heatsink contact with the GPU and added pressure. The areas behind the GPUs have been left exposed since the circuitry is raised slightly higher than the rest of the components. The two rubber spaces at the edge of the card are presumably to prevent a second card above it from drooping under its weight. By allowing a small gap between two cards in CrossFire, the top card receives better airflow.

The fan

The HD6990 uses a centre positioned blower type fan. Rather than placing the fan at the end whereby one GPU ends receiving warmer air from the other, this placement allows air to be blown evenly onto both heatsinks on either side. The blower type fan is more effective at pushing air sideways across the heatsinks but unlike the bladed GTX590 fan, it is harder to draw air in. The fan is only slightly smaller than the 80mm fan on Nvidia’s GTX590. HIS have opted to place their brand sticker onto the fan rotor. Again, the single fan has the arduous task of cooling two already hot running GPUs. The fan has PWM functionality and its speed can therefore be controlled manually or automatically through a temperature profile.

The rear exchaust vent

Inevitably, the downside of the cooling solution is that air is exhausted from either end of the graphics card. On this side, hot air will be pumped back through the vent into the case so adequate airflow is necessary.

The side profile

On the side of the shroud, we see the ribbed design that has been characteristic of AMD’s mid and high end cards this generation. They follow AMD’s black and red colour theme.

The two 8 pin PCIe power connectors

Like the GTX590, the HD6990 makes use of 2 8 pin PCIe connectors to achieve its substantial 375W TDP. Each connector can draw 150W from the 12V rails and the PCIe slot provides an additional 75W for a total of 375W. Although HIS bundle two Molex to 8 pin adapters, it is highly recommended to buy a power supply from a reputable brand which should come with dedicated 8 pin PCIe cables. Should you find yourself needing adapters, it is a sign that you need a new power supply. The connectors are ideally situated on the side of the card to avoid conflicts with HDD cages or other components given the already lengthy size of the card.

The CrossFire connector and BIOS switch

A single CrossFire connector is built onto the card because CrossFireX is currently limited to 4 GPUs. Since the HD6990 already has two, an additional connector is not necessary. Most will probably find the HD6990 enough for their gaming needs regardless of settings.

Previous incarnations of a physical, switchable BIOS switch were seen when the 6900 series first appeared on the scene. These BIOS switches enabled the end user to have a 'stock' BIOS and a further BIOS which could be edited by the user to setup the card how they wished. This time however, AMD have seen fit to pre-overclock a second BIOS on your behalf allowing you to run the card in either stock or overclocked formats. The stock speed of 830/5000 is attained in position 1 with a voltage set to 1.12v, while position 2 increases this voltage to 1.175v allowing the clock speed to be raised to 880/5500. Also known as AUSUM mode, the second BIOS increases the TDP to 450W by increasing the PowerTune limit by 20%, which can also be set manually via AMD CCC Overdrive. 450W is beyond the rated specification of the 8 pin connectors but they will certainly cope as long as the power supply is branded and up to the task. If nothing else, it’s a welcoming change from the restricted GTX590.

The I/O plate

As the ASUS HD6990 is a reference design, it matches the AMD specification for display outputs. From left to right there are four mini-DisplayPort connectors and a single DL-DVI port supporting up to 2560x1600 single resolutions. The five connections allow five screens to be supported. Should you have a Multi-Stream Transport hub (MST), a sixth screen can be added to complete that Eyefinity setup you have dreamed of. The main advantage of the new DisplayPort standard is the double bandwidth over the previous 1.1 ports, taking it from 10.8Gbps to 21.6Gbps. In real world applications, it means that a single port can support up to 2 2560x1600 monitors and 4 1920x1200 monitors through daisy chaining or by using the MST hub. Unlike the HD6970/HD6950, no HDMI ports are present and HIS haven’t bundled an adapter. It highlights AMD’s aim of driving the DisplayPort standard into the mainstream. The top is of the I/O plate is completely vented to exhaust as much hot air outside of the case as possible.

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