Water Block Deconstructed

XSPC designed the Razor GTX680 water block with four distinct layers. The top brushed-aluminum plate and the acrylic layer are held to the block by the five inside black screws, sandwiching the acrylic layer between the aluminum and steel plates. The four screws on the outside left and right sides of the top layer hold the top plate to the acrylic layer only and do not pass through to the steel plate. Both the top plates have cut-outs for the multi-port connect, which is bolted directly to the block. The acrylic layer also has a cutout in the lower right corner to make room for capacitors and power components on the PCB.

The multi-port connector is directly bolted to the block with four screws. The inlet and outlet holes for water channels are defined by the holes in the steel plate. The steel plate is held to the copper under plate by nine steel screws. From the under-view of the block, you can see that those nine steel screws are the only screws going in to the copper plate. The five screws from the upper layers are affixed to the steel plate only. The steel plate has a cut-out in the upper center-right quadrant to make room for capacitors and power circuitry on the PCB.

With the steel plate removed, you can see how the steel screens and the multi-port connector screws work in concert to create a a water tight seal between the steel and copper plates. The copper plate contains two o-rings, an outer o-ring sealing the block and an inner o-ring preventing water into the screw hole located in the center of the block. Both o-rings site in pre-formed channels directly milled into the block by the fabrication process, ensuring a perfect seal. While some of the screw holes look to be in close proximity to the outer o-ring channel, XSPC engineered the block to exacting specifications to negate any overlap between the two.

The block's inlet is the channel to the left. The water enters the block and is forced down over the first set of memory chips. Then the water flows through the micro-channels sitting on top of the GPU chipset. The micro-channels have two functions. First, they increase the surface area over the hottest part of the video card, ensuring optimal heat transfer from the chipset. Second, the micro-channels force an increase in the water velocity because of the pressure increase caused by entering the channels and the decrease on the other side.  The increase in ther coolant velocity ensures better heat transfer to the coolant and dissipation from the GPU. While a pin matrix-style channel design may have netted an increase in heat transfer and dissipation, the micro-channel design does its job flawlessly.

The only downside with using a micro-channel design is the increase in flow restriction inherent in its use – pressure builds up on the inlet side because water flow is restricted by the micro-channels. While the water velocity through the micro-channels is increased, the flow rate over the entire system decreases because of the micro-channels.

Once the water exits the micro-channels over the CPU, the coolant flows over the remaining memory chips and the VRM circuitry. Notice that XSPC designed the Razor GTX680 block with a pass-through for the water, splitting the flow. In splitting the flow, XSPC may have found a way to increase the coolant flow rate, combating the negative effects of the micro-channels.

The coolant outlet channel is the upper right channel on the block, just above the inner o-ring.

The multi-port connector sits at the top of the block, held to the steel and copper plates by four screws. The connector contains three inlet ports on its left side and four outlet ports on its right. The three inlet ports are in a line on the top, outside top, and bottom of the connector with the top and bottom ports forming a pass-through. Similarly, three of the outlet ports are arranged in a line on the top, outside top, and bottom with the forth outlet port on the outside right of the connector. The variety of inlet and outlet ports available allow for better flexibility when linking the blocking into the reset of the system water loop.

The under side of the connector contains the contact points between the connector and the block. The connector contains a built in guide to ensure proper construction when the block is disassembled for cleaning. Further, both of the channel holes have o-rings sitting in pre-formed channels, ensuring a water-tight seal between the connector and the steel plate.

The acrylic middle layer contains LED ports along the outer left and right sides of the plate, capable of housing 3mm LEDs. If you choose to use different LEDs than those included with the block, make sure that the selected LEDs have wire leads that can accommodate the 12 inch span between the left and right side LED mounts on the block.

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