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The BFG 7800 Series Cooler |
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Pretty, pretty, pretty… and useful |
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by Josh Walrath |
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Performance Perhaps the best part of this cooler is how it works. I applied AS5 to the G70 core, and installed the BFG heatsink and fan (at this time BFG is using Arctic Silver 5 for their thermal material). The stock cooler used the stock Shin Etsu thermal material. Testing was done in a closed case with ventilation at an ambient room temperature of approximately 18 C. A windowed 3D application (RTHDRIBL 1.2) was run while the temperature was recorded from the NVIDIA temperature probe built into the driver set. While it may not be the most accurate method for overall temperature, we are more interested in the deltas between BFG and stock.
We can see that the stock cooling solution is all one piece, so the core and the memory are not isolated from each other. While it may help cooling performance overall, most likely the memory is heating up far more than if they were separately cooled. The first set of tests looked at the performance of the BFG cooler vs. its stock counterpart at the highest overclock that could be achieved by the card with stock cooling. The next set of tests looked to see how well the cooling scaled with overclocked performance. Results Something to keep in mind is that the GeForce 7800 series downclocks the core speed when running in only 2D mode. So, no matter how the card is overclocked, it will always revert to the 2D speed (unless you specifically request that it not do that, which is not necessarily recommended). In this case the 2D speed is 300 MHz core and 600 MHz (1.2 GHz effective) memory.
One really neat aspect of this design are the posts used on the cooler. Positioning a standard cooler over the GPU and then trying to hold it into place while screwing it in is not terribly conducive to keeping an even layer of thermal compound. With the BFG cooler, once the compound is in place, the cooler is placed over the holes in the board and seated over the GPU. This allows the user to manipulate the board without fear of smearing the thermal compound around before the final screws and fasteners are set in place. For the first set of tests we overclock the card to its maximum OC speed with the stock cooler, which is 498 core and 655 MHz (1.31 GHz effective) memory. Idle and load temperatures were taken.
Even at idle we see a significant drop in heat with the BFG cooler. NVIDIA spec’s their chips to run at 100 C, and so as long as it keeps “fairly” cool then NVIDIA doesn’t care if the stock cooler hits close to 90 C. At both idle and load the BFG product is a good 8 degrees C cooler than stock. Over time, once the AS5 has cured more, performance most likely will improve For the next set of tests we see how the BFG cooler scales with clockspeed. All of the idle results were 49 C, just as above. The load temps are what we are interested in.
At each MHz range the BFG cooler again shows significant improvements over the stock cooling solution. The stock cooler is by no means a poor design, but it just is not as effective as the BFG product for handling the thermal load.
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Copyright 1999-2005 PenStar Systems, LLC. |
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