Powercolor LCS HD 6990 4GB Reviewccokeman - September 5, 2011
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The PowerColor HD 6990 LCS looks decidedly different from the reference-cooled card. First off, the card is thinner so it only takes up a single slot, leaving expansion slots open for a sound card or PCIe Solid State Drive. The top view shows off the well built nickel-plated EK block with PowerColor and LCS HD 6990 logos etched in the the acetal cover. While looking much better than the reference version, the underlying PCB and components are straight out of the AMD playbook, as the base for this package is a reference card. The past has shown this to be a pretty potent combination, as most liquid cooling blocks are made for reference-based video cards. Even though the EK waterblock is stout enough to keep the HD 6990 from flexing, the aluminum back plate of the reference cooler is retained to act as a passive heatsink for the memory modules on the back side of the PCB. EK has received a lot of bad press as of late over the nickel-plating process it uses, but has now switched to a more durable solution for its blocks. If anything should happen with the finish, PowerColor has your back with its warranty process and has this item covered just in case. Specifications mirror the reference card with clock speeds of 830MHz on the Cayman XT cores and 1250MHz on the 4GB of GDDR5. The AUSUM switch is used to bump the GPU core clock speeds and voltage up to 880MHz and 1175mv, respectively, to take advantage of the main benefit of a liquid cooled video card — reduced temperatures and improved overclocking headroom.
Display connectivity on the PowerColor HD 6990 LCS mirrors the reference cards with a single Dual Link DVI port and four DisplayPort 1.2 ports. For every monitor connected other than the primary DL DVI, you will either need a DisplayPort-capable monitor or use an adapter to connect to the card. The bundle shipped with the PowerColor LCS has this problem covered. This configuration is optimized for Eyefinity setups with up to five monitors. To get to six, a Multi Stream transport hub or DisplayPort monitors that support daisy chaining will be needed. The factory dual-slot bracket is gone and in its place is a single-slot bracket that allows access to more of the motherboard's expansion slots. The back end of the card is quite spartan, without anything of interest other than a few glimpses of the nickel plating.
A single CrossFireX connection is all that is needed as 4-way CrossFireX is the maximum amount of GPUs supported currently by the technology. Right behind the CrossFireX bridge connection is the AMD-named AUSUM (Antilles Unlocking Switch for Uber Mode) switch. On reference cards, this switch is covered with a warning that states that AMD is not responsible for any damages incurred by using this second profile. The reason is that when put into the second position, the GPU core voltage is increased to 1175mv from 1120mv, as well as getting a 50MHz bump in GPU clock speed to 880MHz. It's a cool tool that works as advertised. Be warned that by switching this switch, the power profile is bumped from a 375 watt to an up to 450 watt profile. To feed the power needed to run this card, a pair of 8-pin PCIe power connections are employed in the reference location on the top edge of the PCB.
The EK Waterblocks' nickel-plated block connects to the rest of the system with a series of adapters that terminate with 1/2 inch or 3/8 inch barbed fittings. The block has plugs that can be removed with the included hex wrench to change the orientation of the water inlet and outlet fittings. When screwed into the back side of the block, the included fittings need to use both the extender and spacer to fit above the lip of the backplate. The quick and dirty fix is to use a fitting that will fit into the allotted space, like the Danger Den fatboy fitting. There is nothing wrong with using adapters, but in my eyes it is just one more opportunity for a leak.
Integrating the PowerColor HD 6990 into a new or previously installed liquid loop is a simple matter of attaching the tubing to the system. PowerColor has a great tutorial in the documentation it provides the end user with all the direction needed to get the HD 6990 LCS up and running. Now that it is installed in the test rig, it's time to see if the HD 6990 LCS will deliver the goods.