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PowerColor Radeon HD 5870 LCS: The GHz Limit, Broken


Installation requires the user to attach the card to a separate liquid-cooling system. Typically, I would expect that buyers of this card will own a pre-existing liquid-cooling system for their CPU and will simply add the Radeon HD 5870 LCS to the circuit.

We're testing this video card's limits, so we will dedicate a Koolance Exos-2 system with a 750W cooling capacity exclusively to the task.

As we mentioned previously, we'd have preferred some documentation about the proper way to install the coolant hoses. Since we'd taken the block apart and examined it, we chose the ports that would force the coolant flow first to the GPU and then to the memory before being sent to the radiators for cooling.

Once the hoses are attached and the fittings are tightened, the procedure is the same as it is with any liquid-cooling system. We first ran the coolant through the card without plugging the board into our test motherboard, ensuring there were no leaks and to force any air pockets out of the block. Once we were satisfied that the air bubbles were gone, we simply plugged the card into the motherboard and secured it.

We'll be pitting PowerColor's Radeon HD 5870 against two Radeon HD 4890s in CrossFire. This should be an interesting comparison because the prices are similar (if you're comparing reference card to reference card, that is; PowerColor's water block naturally adds cost just as it would if you were to purchase water-cooled 4890s) and we expect performance to be in the same ballpark, too. However, we're counting on the Radeon HD 5870 to use far less real estate and power than two Radeon HD 4890 cards.