A closer look at Thermal Armor
By far the most unique element of the Sabertooth P67 is the Thermal Armor covering the majority of the board. Asus didn't just employ the shroud for looks, though. The armor was designed to direct airflow to board-level components and shield them from heat generated by expansion cards. Shielding components fits in with the armor theme, but things get a little complicated when you take a closer look at how airflow might be used to cool the motherboard.
Generating airflow for the Thermal Armor requires one of two things: a 50-mm "assistant" fan that screws into the portal pictured above or a CPU cooler whose fan blows down, toward the CPU socket. The assistant fan is an optional component and doesn't come with the Sabertooth. According to Asus, it would have been too expensive to put the fan through the validation and reliability testing required for TUF-series components. Asus thinks end users will be picky enough about noise levels to want to choose their own fan, anyway.
One could always rely on the airflow generated by CPU coolers that blow down toward the socket. Intel's stock coolers have used this approach for years, but the tower-style designs that have become almost ubiquitous among aftermarket coolers don't—they generate airflow parallel to the motherboard, which is of little help to the Sabertooth's armor.
Popping off the shell reveals little in the way of ducting or internal channels to shape airflow. However, there is plenty of internal scaffolding to add stiffness to what amounts to a thin, lightweight plastic piece.
The armor is surprisingly sturdy given how little material has been used. A dozen screws affix the shroud to the board, ensuring that it won't rattle around or vibrate in the company of high-speed fans and whirring hard drives. The screws are easy enough to remove, but eight of them are on the back of the board, making it impossible to pry off the armor with the Sabertooth installed in a case.
Undressing the Sabertooth reveals her naughty bits in all their glory. This is still a good-looking board with the armor removed, and I suspected it could be a cooler one, as well. Thermal Armor might shield the board from heat generated by power-hungry graphics cards, but it also prevents the airflow generated by system fans from cooling motherboard components.
Fortunately, the Sabertooth comes equipped with a slew of temperature sensors to help us evaluate the usefulness of its Thermal Armor. In addition to the temperature sensor in the CPU, the board has 11 different probes covering everything from the voltage regulation circuitry to the USB 3.0 and 6Gbps SATA controllers. These temperatures can be monitored with a new Thermal Radar application included in Asus' AI Suite software for Windows.
The Thermal Radar app is pretty slick. It includes a dose of voltage monitoring and some very detailed fan speed controls. Users can define custom fan speed profiles for the CPU, system, and assistant fan headers. Three target points can be set per profile, and the reference temperature can be tied to a single probe or split between up to three. There's even a set of sliders to adjust the weighting for profiles based on multiple sensors.
Armed with Thermal Radar, we set out to test the usefulness of the Sabertooth's outer skin. We tested the board on an open test bench and in an Cooler Master Cosmos enclosure with the CPU strapped to a tower-style Intel cooler and a stock unit that blows toward the socket. Asus wasn't able to provide us with an assistant fan by press time, so we had to test without—that is, after all, how the board is sold.
Overall, Thermal Armor looks like a very bad idea. When we subjected all the configurations to a combined CPU and GPU load, component temperatures were hotter with the armor in place than with it removed. The differences weren't insignificant, either. Component temperatures were more than 10°C higher when the armor was used in conjunction with the stock cooler, I suspect because the air being blown into the shroud had already been warmed by the CPU heatsink. This was true not only on an open test bench, but also in our tower enclosure.
Letting the system idle produced better results, at least when the Sabertooth was run in a case with the stock Intel cooler. In that config, and only when idle, component temperatures were 3-4°C cooler with the armor installed. Success! Sadly, this advantage disappeared when we switched to a tower cooler or an open test bench.
We contacted Asus about our results, and the company said the effectiveness of Thermal Armor will depend on one's case, cooling, and system configuration. I'm a little dubious that lower temperatures can be achieved when the airflow is coming from a CPU cooler whose heatsink is being warmed by a loaded-up processor, though. I'm also discouraged that component temperatures were so much higher with what amounted to a pretty standard system configuration. For a lot of folks, Thermal Armor may do more harm than good.