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ASRock X99 Extreme6/ac Motherboard Review

Featuring the same wireless controller as its closest competitor, ASRock’s X99 Pro adds a second gigabit Ethernet controller and removes a few pathway sharing issues. Have we finally found a value-winning solution for high-end LGA 2011-v3 buyers?

Our Verdict

Similar in many ways to the Asus X99 Pro, ASRock’s $15-cheaper X99 Extreme6/ac appears to be worth exactly $15 less than that competing product.


  • The X99 Extreme6/ac includes Broadcom’s high-end 802.11ac Wi-Fi / BT 4.0 module.


  • The lack of PCIe lane switches make the X99 Extreme6/ac a 2-way SLI board with 3-way SLI potential.

The Lane Games

More PCI Express connectivity is one of the most prominent reasons to buy an LGA 2011-v3-based platform. Lots of CPU cores are important to certain power users as well, but those PCIe lanes and the four-channel memory controller are why the processor interface is so much larger than Intel's mainstream LGA 1150.

This is a motherboard review after all, and it’s easy for those of us who need extra pathways to see that 40 lanes of PCIe 3.0 are twice as many as 20. Intel even says that 2011-v3’s lanes can be divided across five slots, compared to LGA 1150’s three.

But the tech specs get more complicated after that, and the struggle against those complications are where we often see great ideas fall apart. The first problem is that Intel reserves the 40-lane PCIe 3.0 controller for its top two Core i7 models (currently, the -5960X and -5930K). Lower models like the -5820K get a 28-lane controller. Yet, even with only 28 lanes, we should be able to get three-way SLI at x8-x8-x8 and have four lanes leftover for a PCIe 3.0 x4 SSD, right?

ASRock X99 Extreme6/ac
PCB Revision1.07Voltage Regulator12 Phases
ChipsetIntel X99100.0 MHz BCLK99.94 (-0.06%)
I/O Panel Connectors
P/S 21CLR_CMOS Button1
USB 3.06Digital Audio OutOptical
USB 2.02Digital Audio InNone
Network2Analog Audio5
eSATA1Other Devices2x Wi-Fi Antenna
Internal Interfaces
PCIe 3.0 x16 (-5960X, -5930K)3 (x16/x16/x8) SLI x3, CrossFire x3 M.2 disables x8 slotPCIe 3.0 x16 (-5820K)3 (x16/x8/x4) SLI x2, CrossFire x3 M.2 disables x4 slot
4-Pin Fan23-Pin Fan4
PCIe 2.0 x16NonePCIe 2.0 x12 (+1x Mini PCIe, Filled)
FP-Audio1S/PDIF I/ONone
USB 3.02 (4-ports)USB 2.02 (4-ports)
Internal ButtonsPower, ResetInternal SwitchDual BIOS Selector
SATA 6.0 Gb/s10 (Shares eSATA, M.2)SATA ExpressNone
Diagnostics PanelNumericOther ConnectorsCOM, TB_Header, HDD-Saver, USB Type-A
Mass Storage Controllers
Chipset SATA10x SATA 6Gb/s (Includes M.2, eSATA)Add-In SATANone
Chipset RAID Modes0, 1, 5, 10 (Ports 1-6)USB 3.0ASM1042e PCIe ASM1072 Hub
Primary LANWGI218V PHYSecondary LANAR8171 PCIe
Wi-FiBCM4352 PCIe 802.11ac dual-band / BT 4.0BluetoothBT 4.0 / Wi-Fi Combo
HD Audio CodecALC1150DDL/DTS ConnectDTS Connect
WarrantyThree YearsPrice$295

In unfortunate mimicry of its closest competitor, ASRock doesn’t split the first slot into x8 mode, even when the lanes are needed elsewhere. Perhaps this is a marketing decision. Or perhaps the engineers just wanted to save a few dollars in PCIe pathway switches. At any rate, the X99 Extreme6/ac bears the same three-way SLI caveats as the recently-reviewed Asus X99 Pro. The Core i7-5820K processor breaks three-way SLI capability, and a PCIe-based M.2 drive disables that slot entirely. The good news for those whose hardware choices are unaffected is that—unlike its long-divorced partner—ASRock didn’t screw up the X99 Extreme6/ac’s PCIe 2.0 slots.

ASRock’s always tried to offer its customers a few more features for a little less money, so let’s see what other advantages the X99 Extreme6/ac holds…