Our first round of tests focused on benchmarking the two subject cards in a single-card configuration in our large ATX-based test system, as well as testing the 780 Ti reference blower-style model in the compact Silverstone SG08-based system.
Note that the MSI GTX 780 Ti actually came factory overclocked, boosting to a core speed 118MHz higher under load than the reference model. To make the testing done on these two cards comparable, we manually overclocked the reference card to the same level. Therefore, both cards operated at 1124MHz during all of our testing. But that wasn't the only challenge we faced in setting up the tests, as you'll read below.
In addition to compensating for the varying clock speeds of our two sample cards, we also faced a bigger challenge to drawing relevant conclusions on cooler effectiveness: fan profiles. This simple concept proved somewhat vexing, and in fact seriously undermines most video card comparisons you'll read on the Internet. You see, every manufacturer sets its own, unique fan curve for its cards, and while Nvidia establishes maximum temperature targets for its GPU Boost technology to run optimally, these do not necessarily inform the fan curves. For the GeForce GTX 780 Ti, maximum boost can only be achieved at a temperature below 83C by default; at temperatures above that, power will be cut to reduce boost and temperature. These targets can be adjusted using after-market overclocking tools, but that wasn't what we wanted to do here. Instead, we wanted, as much as possible, to provide an apples-to-apples comparison of cooler noise and effectiveness. That meant that the coolers had to be accomplishing the same task, not different tasks. A loud fan cooling a GPU to 60C cannot be equated to a quiet fan that allows a GPU to bump up against its temperature threshold. At the outset, we can't say which one actually works better, only that the manufacturers have established different fan profiles.
What was the solution, you may ask? Well, we decided to continually run our cards through an intense benchmark loop until we could establish the minimum fan speed at which their coolers could maintain a temperature of 80C. We also had to hold ambient temperatures constant; throughout our tests, the ambient temperature was between 64 and 65 degrees Fahrenheit (18C). In the benchmarks that follow, we provide fan speeds, sound level measurements, and temperatures for our test cards in our two test systems. We used an Android-based decibel meter, along with onboard temperature and fan monitoring as reported by the MSI Afterburner overclocking utility.
The benchmark we used for single-card testing was Unigine Valley, a technology demonstration released in 2013. Because it outputs frame rendering rates, we could also confirm that our test cards, as manually overclocked and used in two different systems, were actually performing at the same levels. As can be seen below, the performance in all three test scenarios was identical, within a very small margin of error. Both systems used Intel quad-core CPUs overclocked to 3.9GHz, although the 500R system used a 4770K with Hyperthreading, while the SG08 used a 4690K. The 500R also used faster RAM (DDR3-2400 vs. DDR3-1866). We specifically chose a benchmark that would be GPU-limited to eliminate the effect of these differences.
OK, now that we've established that our cards are performing the same function, let's see what happens when we ask their coolers to also perform the same function. Our first set of sound level and temperature benchmarks comes with the cards at idle at the Windows desktop.
We've grouped the results by card and by case. To make comparisons easier, just focus on the variables that show the greatest delta. Comparing the two types of coolers in the 500R case (the first two sets of benchmarks), we see that the GPU temperature and fan speed differ the most. The open-air MSI model is cooler by 3C, but is also running its fans at a higher speed (which happens to be the minimum level possible with this card, 34%). As a result, it's no quieter than the reference 780 Ti, and in fact appears to be louder. In our liquid-cooled benchmarking rig, most of the noise is coming from the water pump, however, so in this situation, the open-air and reference blower-type cooler are basically indistinguishable.
Flipping to a comparison of the reference 780 Ti in the 500R case and the SG08 mini-ITX case (the second and third sets of benchmarks), we can see more dramatic differences. The CPU is obviously much warmer in the ITX case, given that it's passively-cooled rather than liquid-cooled. More importantly, the system is much quieter, running at only 30 dB, versus 35 dB, and thus at our testing room's noise floor. There you see the upside of using a passively-cooled CPU and a case with no front air intakes! Also of note is the fact that the 780 Ti actually runs a bit cooler in the SG08, despite the case having no intake fans, versus the 500R and its twin 120mm front fans and huge 200mm side fan. It's frankly amazing that the comparatively-tiny turbine fan of the reference GTX 780 Ti can cool the card nearly as well as the open-air MSI model in a huge case with huge amounts of airflow, at least at idle. This is our first indication of why reference blower-style cards still have their place, and why AMD's lack of workable blower-style solutions for its current Radeon lineup might be costing it sales. This could be particularly true among OEM vendors, who have to compensate for modifications a user may make to his or her system, perhaps to the detriment of airflow. Again, we're sorry we couldn't bring you measurements of the open-air MSI model in the ITX case - our bet is that the CPU temperature would have been higher, while the GPU temperature and sound level would have been the same, if not slightly lower.
Our next set of benchmarks returns us to Unigine Valley, where we previously benchmarked rendering performance. This time we're benchmarking cooler performance, of course:
Remember, our goal here is to have the coolers perform the same task, in this case to hold the GPU core at 80C. That's the one variable that does not change in our three test situations. Focusing on the MSI open-air cooler versus the EVGA reference cooler in our main test system, there are some stark differences in fan speed, but not so much in sound level, and none in the CPU temperature. Ultimately, the use of a liquid cooling system in this system means the type of video card cooler used ends up being insignificant - the CPU cooling system is essentially self-enclosed and unaffected by additional hot air inside the case. For better or for worse, the CPU cooler may also be masking the sound level difference between the two coolers - when running the EVGA reference model at a 57% fan speed, the system is only 1 dB louder than it is with the MSI model, which runs at a fan level of just 39%. Our guess is that the MSI card is operating very close to the noise floor of the system at load. Remember, it was 35.5 dB at idle; at load it's just 36.5 dB.
Turning to the reference vs. reference tests, we can see that the card's cooler performs identically in the tiny ITX case, despite the lack of any intake airflow beyond what the card can pull from outside the case. The GPU is again operating at 80C and 57% fan speed, and in fact is quieter in the ITX case, where all the noise is being generated by the video card. Because the case's single 140mm exhaust fan operated at under 1000 RPM, it could not be heard above the sound of the reference Nvidia fan. As impressive at its performance is, it quite can't match the open-air MSI 780 Ti in the large 500R ATX case. At 37 dB, the reference 780 Ti is making more noise on its own than the entire cooling system in the ATX case, which registers at just 36.5 dB, liquid CPU cooling pump and all.
So, what can we make of these results. Well, it's truly a tale of two scenarios. In a large case with ample airflow and a liquid CPU cooling system, modern GPU coolers simply don't have a signficant effect on noise levels. As many an enthusiast has been caught saying, "my card is silent - I can't hear it above my case fans." Of course, this observation does not prove that the card is silent, but it does tend to to show that in many situations, video card cooler noise need not be a determining factor in selecting a card. On the flipside, the design of the cooler is of the utmost importance in a small system, if for no other reason than that bigger open-air coolers might not fit, which we learned the hard way. Just as important, however, to system builders, be they OEMs or a first-time hobbyist at home, is that a blower-style cooler takes a lot of the guesswork out of the cooling equation. As can be seen, the cooler is equally effective regardless of the case in which it is utilized.
For our next set of tests, we combined our two sample 780 Ti cards for some dual-card SLI testing... things are about to get interesting!