ASRock announced a new addition to its high-end Fatal1ty product series, the ASRock Fatal1ty Z170 Professional Gaming i7, which is positioned as its highest-performance Z170 motherboard. But does it really offer more than ASRock's other Z170 boards?
At first glance, the ASRock Fatal1ty Z170 Professional Gaming i7 seems like an excellent motherboard jam-packed with the latest features, like SATA Express, M.2, USB 3.1, DDR4, and support for Skylake. Although ASRock's board unquestionably offers more connectivity than other Z170 ASRock boards, it is questionable to what extent users can take advantage of these features.
The HSIO Problem
Like all Z170 motherboards, the ASRock Fatal1ty Z170 Professional Gaming i7 features a total of 26 lanes from the chipset. On this motherboard, six are consumed by USB 3.0 ports directly from the chipset itself, while at least one (likely more) additional HSIO lane is used to connect a USB controller, which provides two additional USB 3.0 ports, as well as two USB 3.1 Type-A and Type-C ports.
The motherboard also supports a total of 10 SATA 3 ports alongside three SATA Express connectors. Similar to USB 3.0, these connections consume at least seven HSIO lanes. Six of the HSIO lanes are consumed and used directly as SATA 3, while the extra four SATA ports and SATA Express connectors will need at least one HSIO lane for a SATA controller.
Without considering anything else, that drops the free HSIO lanes down to six, and that is assuming that only a single controller each is used for USB and SATA, which itself would create a serious bottleneck for devices connected to those controllers.
Each HSIO lane is equivalent to a single PCI-E 3.0 lane, which is capable of roughly 8 Gbps of bandwidth (985 MB/s). Each SATA 3 port is capable of 6 Gbps (600 MB/s), and SATA Express requires 16 Gbps (1969 MB/s) of bandwidth to operate at full speed. Therefore, if ASRock is running all of these SATA devices off of a controller with more than a single HSIO lane, there will be a significant bottleneck.
Even if ASRock allocated more HSIO lanes to those controllers, there is still a connectivity issue. The motherboard also contains two gigabit Ethernet Intel NICs and two PCI-E x1 connectors, each requiring an HSIO lane, dropping us down to two remaining unused HSIO lanes.
ASRock also placed three M.2 ports and an mSATA connection on the motherboard. The M.2 ports are capable of consuming four HSIO lanes each, driving us way beyond what the Z170 chipset is technically capable of.
How Is This Possible?
The only practical way that ASRock could have added all of these devices is to use HSIO lanes for multiple devices. This may sound like a good idea, but HSIO lanes are capable of feeding only one device per lane at a time. What this means is that although you have an abundance of connectivity options, you can't actually use all of them at the same time.
ASRock doesn't come out and say this, but it doesn't hide the information either, for those who examine the specs. All of the M.2 ports (each with a separate lane) share lanes with two SATA ports and a SATA Express connector, so using an M.2 device instantly disables at least three other connections.
|M.2_1||SATA3_0, SATA3_1 and SATA_EXP0|
|M.2_2||SATA3_2, SATA3_3 and SATA_EXP01|
|M.2_3||SATA3_4, SATA3_5 and SATA_EXPO2|
Does It Matter?
Although many may not see this as a serious issue, as users would need to use numerous connectivity devices before this becomes a problem, the extravagant amount of connectivity this board professes to offer is one of the attractive things about it, and many users will likely buy it without realizing they can't use most of the storage connections at the same time. Because there is no reason to pay for extra features you aren't going to use, it would be prudent for users to examine ASRock's other high-end boards which are capable of the same performance but with fewer connectivity options and a lower price tag.
There is currently no word on pricing or availability.
Michael Justin Allen Sexton (or MJ) is a Contributing Writer for Tom's Hardware. As a tech enthusiast, MJ enjoys studying and writing about all areas of tech, but specializes in the study of chipsets and microprocessors. In his personal life, MJ spends most of his time gaming, practicing martial arts, studying history, and tinkering with electronics.