Aerocase Condor: A Massive, Passive VGA Cooler

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TEST RESULTS

ON THE 6800GT

The cooler was first installed on an AOpen Aeolus PCX6800GT-DVD256 — a medium-powered video card that features a thermal sensor build into the GPU core. The accuracy of the sensor is unknown, but it is good enough to make relative judgments between the various coolers. Past tests of VGA coolers have also been installed on this card.


This GeForce 6800GT has stood up to a year's worth of abuse around the SPCR lab.

Ambient conditions during testing were 16 dBA and 22°C. Tests were run with the system fan at 12V, 9V, and 7V.

Thermal testing consisted of running two instances of CPUBurn and the artifact scanner built into ATI Tool simultaneously to generate as much heat as possible. An initial test was run with the system fan running at 12 volts, and then the fan was progressively slowed down to make the thermal environment more difficult.

Once the temperature on the card had stabilized, the stress software was left running for at least another 20 minutes while we watched the screen carefully for visual artifacts that might indicate overheating. The last test, with the system fan running at 7 volts, was left running for more than an hour. Even during our most strenuous test, the Condor never allowed our test card to get hot enough that there were visual artifacts on the screen.

Aerocase Condor Test Results (GeForce 6800GT)
System Fan Voltage
GPU
VGA Ambient
CPU
AC Power
System Noise
dBA@1m
12V
84°C
76°C
65°C
229W
26
9V
88°C
81°C
67°C
232W
25
7V
90°C
84°C
70°C
232W
24
Note: The PSU fan ramped up a bit under load to bring the system noise up ~2 dBA@1m over the 22dBA@1m minimum idle noise of this system with case fan at 7V.

Dropped into place on our testbed, the Condor did rather poorly in comparison to other heatsinks that we've tested. This is excusable, since no other passive heatsinks have been tested in this system. However, it's core temperature that counts, and the Condor only barely kept our GeForce 6800 GT below 90°C. That may be good enough for our card, but it doesn't say much for the Condor's potential to cool hotter cards like the X1900XTX, at least not in our low airflow case/system.

Our standardized test system doesn't really give the Condor a fair chance. Passive cooling requires careful attention to system airflow, and our test system is not designed to circulate much air in the bottom portion of the case. The standard edition of the Condor that positions the heatsink over the CPU cooler probably would have done better. We chose this "reverse wing" sample to ensure that the cooler could be used even with large tower heatsinks; in retrospect, perhaps both variants should have been tried.

ON THE X1900XTX

Aerocase's "Preview" Test

Aerocase seems to have fallen into the same trap that we did in their test of the X1900XTX. That test used 3DMark05 to stress the card, but our own testing showed that none of the tests in 3DMark05 managed to stress the card any more than ATI Tool did. Tapping the full potential of the X1900XTX required the SM 3.0 test in 3DMark06 — a much tougher test.

It was with some trepidation that we screwed the Condor onto the X1900XTX — well known as the block heater of graphics cards and said to consume over 120W peak under load. In addition to the Condor, two other heatsinks were tested on the X1900XTX: The stock ATI cooler and our current favorite aftermarket cooler, a Zalman VF900.

Midway through the first stress test, we realized that something was wrong: The AC power consumption was too low. That's significant. Power consumption is the best measure of how much heat is generated by a system, and our test rig was consuming about ~230 watts — almost exactly the same as our previous tests. We had the hottest gaming card on the market and it wasn't delivering. What could be wrong? A careful examination of our test methodology revealed that the software used to generate load — the artifact scanner embedded in ATI Tool — did not stress the GPU enough to heat it up fully.

Several days of research and experimentation revealed a new candidate for stress testing: The first SM 3.0 demo in 3DMark06. This demo pushed the system's peak power consumption to almost 300W, although the average during the test was typically 15~20W lower. Tests were run at 1280 x 1024 resolution (oddly, higher resolutions caused power consumption to drop) with 16 sample anti-aliasing and 6x anisotropic pixel shading enabled. The SM 3.0 demo was set to loop indefinitely during the test, and temperature readings were not made until three loops in sequence generated the same peak temperature.

This stress test is not continuous; each loop required about 20~25 seconds of load time when the card was not being stressed. As a result, the core temperature fluctuated by almost 20°C between each loop. On average, each loop took about two minutes to complete, about a quarter of which was spend with the GPU in idle.

Aerocase Condor Test Results (Radeon X1900XTX)
Cooler
VGA Fan Voltage
GPU
VGA Ambient
Peak AC Power
CPU
Noise of cooler fan
dBA@1m
Aerocase Condor
105°C*
63°C
306W
68°C
N/A
92mm fan @ 12V
86°C
58°C
293W
67°C
24
Stock ATI Cooler
5V
105°C*
70°C
300W
65°C
37
12V
69°C
54°C
280W
62°C
51
Zalman VF900
5V
86°C
57°C
291W
65°C
20
*Test halted when ATI's thermal throttling interrupted the test.
Note: The minimum system noise at low load with the CPU fan, case fan and PSU fan measured 22 dBA@1m. Under full load testing, the PSU fan ramped up to bring the system noise (without VGA card cooler fan) up to ~30 dBA@1m. Under such load, only the stock ATI cooler could be heard distinctly over the rest of the system noise.

In the terrible thermal conditions of our test rig, the Condor was not able to cool the X1900XTX to our satisfaction. In fact, ATI's thermal throttling kicked in just as we were about to conclude that the temperature was stable at 105°C. The power draw that we saw during the test was ~15W higher than our other tests — a sign that the power circuitry on the board was headed towards thermal runaway.

On the other hand, the stock cooler fared no better when undervolted to 5V — and it was still far too noisy at 37 dBA@1m. Presumably, the fan voltage would have been closer to 12V had we let the card control the stock fan. The 12V test (51 dBA@1m) shows the kind of cooling that could be expected if this were allowed to happen. The 20W (!) spread in power consumption between the two fan speeds shows just how necessary that extra cooling is.

Some Extra Cooling

Aware of the limitations of our test system, we decided to try again, this time with an additional fan taped on the floor of the case just in front of the Condor blowing towards the back. We used a 92mm Scythe S-Flex fan, running at 12V. This fan (which measured 24 dBA@1m) added very little noise to the system, especially under load when the fan in the power supply ramped up.

The change was dramatic. The GPU core dropped 20°C to 86°C, equaling the VF900 at 5V. More importantly, the card no longer overheated. That's right, the hottest graphics card on the market, cooled by a passive cooler. Well, not quite; the extra fan is cheating a bit.

CONCLUSIONS

Cooling an X1900XTX is a tough job under any circumstances, and doing it quietly is an exceptional feat. We are confident that, if attention is given to system airflow, the Condor is capable of cooling any card on the market.

That said, we do not recommend using the Condor with an X1900XTX because we do not recommend using a card that hot in any quiet system. The extreme amount of power sucked up by the X1900XTX is almost certain to cause any power supply fan to speed up. Even the Antec Neo HE in our test system (ducted with fresh air to keep the fan speed down) ramped up; no other fan-cooled power supply would fare better. There is little point in buying a passive cooler for a card that will increase noise elsewhere in the system.

Because of the need for good system design, the Condor will perform best in the hands a of meticulous, experienced user who understands how to optimize airflow in a PC. It has excellent cooling potential, but it cannot just be dropped into any system with good results. As we discovered in our early tests, putting the cooler in an area with little airflow cannot result in good cooling performance. On the other hand, if the Condor can share airflow with other system components, one less fan is needed and noise is reduced a bit (or a lot) further.

For all the customization and lack of mass production and distribution, the price of the Condor is surprisingly modest. US$60 is not unheard of for a high-end cooler. The asking price of the excellent Zalman VF900 is as much as US$115, although the wonders of e-tailing keep the average price around US$40. An extra $20 is not a bad price to pay for the jump from low-noise to fully passive. On top of that, the unusual honesty and frankness that is apparent on Aerocase's web site is impressive. Personally, I am willing to pay a little extra for the knowledge that a company is well run, and I'm probably not alone.

It's questionable whether the Condor will see the kind of sales volume of well-established competitors like Zalman. Considering Aerocase's distribution and sales model, it's uncertain whether they are pursuing that kind of goal. The Condor is a niche product, and it fits that niche nicely.

Many thanks to Aerocase for the sample of the Condor and the X1900XTX loaner, and to AOpen for the samples of the VGA card and the motherboard in the testbed.

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Editor's Counterpoint: If you wanted to quibble, you could ask where is the vaunted high technology and engineering of this aerospace design team? It's practical and it works well, but toothpicks?! The Condor is just two lengths of aluminum extrusion glued to heatpipes that join to a basic copper plate. It's the kind of thing that might show up as a DIY project by one of SPCR's dedicated silencers. As Devon mentioned earlier, it's a brute-force approach, hardly subtle... but admittedly still kind of elegant in its apparent simplicity.

My guess is that the company's response would be to say, "Go ahead and DIY." I suspect it could cost you several times Aerocase's asking price in materials and time (especially the latter with trial and error runs), and if the final product doesn't work well, you may end up with a useless once-very-expensive video card with no one to blame but yourself. Also, the number of PC enthusiasts with the skills, tools and time to pull off such a cooler is extremely small.

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SPCR Articles of Related Interest:
Fanless PCIe Graphics Cards from Asus and Aopen
Gigabyte GV-N66256DP Fanless AGP video card
VGA Cooler Roundup: A Thermalright, two Zalmans, and an Arctic Cooling
Sytrin KuFormula VF1 Plus Graphics Card Cooler

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