Design and Features
The ASUS Sabertooth X79 looks highly promising at first sight. Its capabilities are obvious right away thanks to the color coding of the connectors. You don't have to look up the purpose of each connector in the user manual, on the mainboard's PCB or at the manufacturer's website. For example, the mainboard’s expansion capabilities include one PCI, two PCI Express 2.0 x1 and three PCI Express 3.0/2.0 x16 slots. Two of the PCIe 3.0/2.0 x16 slots can work in full-speed mode whereas the third one, at x8 speed. You won't have any doubts about where to install your graphics cards because the full-speed PCIe x16 slots are beige and the x8 slot is dark-brown.
It is also easy to plug in your disks. The Intel X79 Express chipset provides four SATA 3 Gbit/s ports, so these are obviously the four black-colored connectors. Two pairs of light-gray and brown connectors are placed on both sides of them, but the gray ones have an ASUS SSD Caching sticker. This is the name of a technology similar to Intel Smart Response. It allows using a fast SSD as a cache for a conventional hard disk drive. Thus, it is clear that the two brown connectors are the chipset’s SATA 6 Gbit/s ports whereas the gray SATA 6 Gbit/s connectors are based on the additional Marvell 88SE9128 controller. So, we just plug our disk to one of the brown connectors without further thinking.
One of the advantages of the LGA2011 platform is its support for large amounts of memory. The ASUS Sabertooth X79 puts this advantage at your disposal by offering as many as eight memory slots. The product specs inform us that the mainboard supports up to 64 gigabytes of DDR3 SDRAM in quad-channel mode at frequencies of 1066 to 1866 MHz but the actual range of available frequencies is larger since the mainboard's BIOS allows setting the memory clock rate in a range of 800 to 2666 MHz. The digital power system DIGI+ includes, among other things, two separate voltage regulators for memory modules, providing flexible setup options for both the CPU and memory.
We’ve mentioned about that the TUF series features high-quality components. However, the 5-year warranty could hardly be ensured without proper cooling. Many mainboards come with but a small heatsink on the CPU voltage regulator which can get very hot at high loads. On the ASUS Sabertooth X79 this heatsink is connected with a heat pipe to an auxiliary heatsink located near the mainboard’s back-panel connectors. You can even equip it with a fan included into the product box. The auxiliary heatsink is close to the mainboard’s I/O shield and the latter has vent holes for the hot air to go outside.
The photo below shows that the back section of the auxiliary heatsink is covered with a red sticker which must be removed prior to using it. There’s a small fan right above it.
The back panel of Asus Sabertooth X79 has the following ports and connectors:
- PS/2 connector for keyboard or mouse;
- Four USB 3.0 ports (blue connectors) implemented via two ASMedia ASM1042, the third controller like that provides an additional internal pin-connector for two more USB 3.0 ports;
- Six USB 2.0 ports, six more are laid out as four onboard pin-connectors;
- IEEE1394 (Firewire) port implemented through VIA VT6315N controller, the second port like that is available as onboard pin-connector;
- eSATA and Power eSATA 6 Gbps ports (green connectors) implemented via ASMedia ASM1061 controller;
- Optical S/PDIF and six analogue audio-jacks provided by eight-channel Realtek ALC892 codec;
- “USB BIOS Flashback” button;
- A local network port (network adapter is built on Gigabit Intel 82579V network controller).
Now we want to once again praise the extremely helpful firmware update feature called USB BIOS Flashback. All you need to do is connect a USB flash drive with a new BIOS version to the dedicated USB port at the back panel (it’s colored white), press a dedicated button and wait. You don’t even have to assemble your PC completely because this technology should work even if you don’t have a CPU or memory installed. All it needs is power for the mainboard. You can check out the official website for details on this USB BIOS Flashback feature.
Like other ASUS mainboards, the new Sabertooth X79 uses conveniently wide Q-Slot latches on the graphics card slots and one-sided Q-DIMM latches on the memory slots. Besides the USB BIOS Flashback button on the back panel, there is a MemOK! button there that allows the mainboard to successfully boot up in case of memory-related problems. The Q-LED indicators will help you quickly determine at what stage the boot-up process has stalled. The availability of two connectors for CPU cooler fans is an advantage, although only 4-pin fans can be regulated. For example, ASRock mainboards can regulate any fans as one of these connectors is 3-pin on them.
We liked that our large CPU cooler Noctua NH-D14 didn’t prevent us from installing our graphics card into the top PCI Express 3.0/2.0 x16 slot. We had to use the farthest slot on every mainboard from ASRock and Gigabyte we’ve tested because the CPU socket and the first graphics slot were too close to each other on them. So, the Sabertooth X79 seems to be perfect from every side. Indeed, we like everything about it, except for the fans in its cooling system.
We mean the Intel X79 Express chipset doesn’t really need that much cooling. So when we noticed this kind of active cooling in our review of the ASRock X79 Extreme6/GB mainboard, we wanted to put it down as a downside but then we found out that the fan was a mere decoration there. The mainboard’s aggressive speed regulation system didn’t even allow that fan to start up under normal conditions. There was no noise and no wear, so this downside was eventually struck off of our list of that mainboard’s lows.
As for the Sabertooth X79, its fan starts out at 3200 RPM and accelerates to 4000-4300 RPM when the CPU is under load, although the chipset’s temperature only increases from 37 to 38°C. The speed of the chipset fan seems to depend on the CPU temperature rather than on the temperature of the chipset itself. Well, the mainboard has one more advantage we haven’t yet mentioned. It’s TUF Thermal Radar technology.
As opposed to ordinary mainboards which can only monitor system and CPU temperatures, the Sabertooth X79 has extra sensors in different spots of its PCB. The TUF Thermal Radar technology lets you set the speed of any fan basing on a particular sensor or manually. It means we can probably change the speed of the chipset fan to reduce its noise and wear. The small fan wasn’t very loud, actually, because the mainboard cannot regulate the speed of 3-pin CPU fans and the two fans of our Noctua NH-D14 cooler, 120 and 140 millimeters in diameter, drowned out every other noise source when working at their full speed. But rotating at 3000-4000 RPM, the chipset fan is going to wear down eventually and it can’t be replaced easily due to its nonstandard form-factor.
It seems that we can solve this problem by disabling or halting the chipset fan. It didn’t rotate on the ASRock mainboards which had a normal temperature of the chipset, so why can’t we do the same with our Sabertooth X79? Well, because it uses one more exclusive technology.
We first discussed the TUF Thermal Armor technology in our Sabertooth X67 review. That mainboard was wrapped into a plastic case which was supposed to separate mainboard components from such hot devices as a graphics card or CPU. We had some doubts about its efficiency then and we still have them now. For example, the ASUS P9X79 Deluxe uses an additional heatsink connected to the main one with a heat pipe in order to cool the hot components of the CPU voltage regulator. Both heatsinks are open and cooled by the system and CPU fans. This doesn’t work on the Sabertooth X79 because the additional heatsink is separated from the air flow by the Thermal Armor casing. It can only be cooled by its dedicated small fan.
We don’t have any doubts about the efficiency of the TUF Thermal Armor technology when it comes to cooling the Intel X79 Express chipset. The mainboard’s chipset heatsink is not just a piece of aluminum with a fan on top, but a rather sophisticated composite thing. The heatsink itself is small. It is in fact a heat-spreader with a plastic cap that directs the air flow from the fan. This design is efficient but only meant for active cooling. If the fan is turned off, the small heatsink covered with a cap will not be able to keep the temperature low and the chipset will overheat.
So, we can’t disable the chipset fan. We have to wait for it to get noisy or even fail altogether. There’s no doubt that’s going to happen sooner or later, considering its high rotation speed. What to do then? Will ASUS send fans to users at their request or will they have to bring the whole mainboard to a service center?
As for the fan on the CPU voltage regulator, it has a higher start speed of 4000-4300 RPM and accelerated to 7000-7200 RPM during our CPU stability tests. Yes, the CPU cooler’s fans are louder than everything else inside the system case at full speed, but this little monster of a fan just makes itself heard anyway. As opposed to the chipset fan, we have no complaints about this one. The heatsinks get very hot and they do need proper cooling, so we can put up with that. And when this fan eventually gets noisier than usual or fails, we can easily replace it...
Well, we thought it could be replaced easily, but that’s not really so. The fan has a rare form-factor of 35x35x10 millimeters. It's hard to tell why ASUS didn't install a standard 40mm fan which could be replaced easily.
We’ve discussed the cooling system of the ASUS Sabertooth X79 at such length not only to clarify our point of view but also because it's virtually the only noticeable downside of the whole mainboard. The sophisticated chipset heatsink is surely efficient and it makes the active cooling redundant, especially as replacing the fan is going to be problematic. And the cooling system of the CPU voltage regulator would be perfect if it were not for yet another nonstandard fan which can't be replaced easily, either.
We guess the Sabertooth X79 would be ideal if it used a conventional aluminum heatsink for the chipset and a standard 40x40x10mm fan to cool the auxiliary heatsink on the CPU voltage regulator.
All the technical specifications of the Asus Sabertooth X79 mainboard are summed up in the following table: