Sharing the same circuit board, the X99 OC Formula/3.1 and Fatal1ty X99 Professional/3.1 support up to ten SATA drives, two M.2 drives, a mini-PCIe Wi-Fi module (not included), and 4-way SLI/CrossFireX.
ASRock divides its M.2 interfaces between an "Ultra M.2" slot with four PCIe 3.0 lanes and a legacy M.2 slot with two PCIe 2.0 lanes and a single SATA port. Builders can fit an ultra-fast 40 Gbps x4 M.2 and still have room for a second drive using a single 6 Gbps pathway or tandem 5 Gbps pathways for the slower drive, in addition to the super-fast slot. SATA mode over M.2 disables one port (marked "S_SATA_3") from the standard SATA connections.
The only M.2 Wi-Fi modules I’ve seen used a completely different type of slot, which is really a horrible thing for end users. Fortunately, Mini PCIe remains a popular alternative.
The LGA 2011-v3 package supports both 40-lane and 28-lane CPUs, the latter limiting these boards to 3-way SLI/CrossFireX as the bottom slot gets disabled. Slot spacing isn’t a major issue since most performance cards have double-slot coolers, though 3-way SLI is problematic for cards with thicker coolers. That spacing would require a user configuration not-approved by ASRock, requiring the black slot for the middle card and a 40-lane processor. Two-way configurations in the first and fourth slots are virtually unrestricted.
The black slot is quite a conundrum for those who must use it, since it’s tied to the Ultra M.2 interface. It has eight PCIe 3.0 lanes when using a 40-lane CPU, but only 4-lanes when used with a Core i7-5820k. And because it’s the only slot without pathway-diverting switches, it gets entirely disabled whenever an SSD is installed into the “Ultra M.2” slot. The last four lanes of a Core i7-5960x or 5930k simply disappear.
There’s only one good reason to complain about the black slot, though, and the USB 3.1 add-in card is that reason. You might be tempted to use it in conjunction with a couple thick graphics cards, but it’s only going to function if the x4 M.2 slot is empty. Though this won’t matter to most users, it will pose a significant challenge to a few.
Two USB 3.0 front-panel headers are lined up above the graphics cards, at the front of the board, for easy connection. All four ports share a single USB 3.0 chipset lane via a 4-port hub, because you really don’t need full bandwidth to power four USB 3.0 drives at the same time, do you? If you did, the board also has two unshared ports on the rear, along with four shared I/O-panel ports, and you can probably figure out which ports to plug what device into.
Oh, there’s also the FP-Audio header that’s shoved just a little too far into the bottom corner for the cables of some cases to reach, but that’s mostly a case issue. I’ve denounced such cases in my own reviews, but I don’t review every case.
Like its most-expensive rival, ASRock includes LN2-mode and slow-mode switches for extreme overclockers, the latter allowing them to clock the system down to a 12x multiplier to avoid “cold bug” situations when the CPU is unloaded. The longer explanation involves the fact that some overclocks fail at too low a temperature, and the LN2 port can cool off quickly when the CPU is unloaded. Switching to a lower clock before killing the CPU-loading application can prevent this issue.
Two buttons allow users to clock the CPU up and down by BLCK or core multiplier, as well as the CPU cache ratio, core voltage and cache voltage. The “Menu” button allows users to switch between adjustments, while ASRock’s Rapid OC application pops up to show them which item has been selected.
Other OC-friendly features are found in the lower front corner, and include a two-digit status code display, a firmware ROM selector switch, a Direct Key button for powering up directly to the firmware GUI, a regular Power button and a reset button. These boards even include a couple LEDs to indicate which firmware ROM is active.
Also seen above are the two replaceable firmware ROMs, the single SATA-Express extension for SATA ports, and a sticker-covered connector for ASRock’s HDD Saver two-drive power cable. That power cable lets users power down a drive that’s not in use. The HDD Saver application is password-protected, but the password only protects access to that power cable.
Both motherboards include six SATA cables, a PCIe x4 to USB 3.1 dual-port expansion card, a 2-drive HDD Saver cable, I/O shield, software and documentation. The X99 OC Formula/3.1 provides three flexible bridges for 2-3-4-way SLI, while the Fatal1ty X99 Professional has rigid bridges for 2-, 3- and 4-way SLI.