Our next X299 motherboard review shrinks down from the large ATX and E-ATX sized motherboards to the sole Mini-ITX offering for the X299 platform. The ASRock X299E-ITX/ac is a diminutive board that offers nearly all of the same features as its larger counterparts but in a package well suited for SFF systems. Users will find four SO-DIMM DRAM slots for quad channel operations, dual Intel NICs, six SATA ports, three M.2 slots (!), plus integrated Wi-Fi and Bluetooth capabilities. 

ASRock X299E-ITX/ac Overview

The ASRock X299E-ITX/ac is currently the only available Mini-ITX board for the X299 platform. EVGA, MSI, and ASRock do offer MicroATX sized boards, but none are like this. Typically with Mini-ITX boards, their small dimensions yield an obvious lack of real estate for adding functionality. In order to squeeze more out of what was available, motherboard manufacturers have had to be creative, and often built up (quite literally). For example, additional slots on the motherboard to go vertical.

On the X299E-ITX/ac, this means an extra daughterboard slot just behind the back panel IO, and a second on the opposite side of the motherboard. The first pairs a riser card with a single M.2 device, and the second holds a storage array setup. This latter module holds the six SATA ports, as well as external USB 3.0 and USB 2.0 headers. Curiously, that card is large enough to cover the VRM heatsink, which might hinder air flow to the area around there. One of the other major space saving design choices used here is to locate two M.2 slots on the back of the motherboard. Impressively, three M.2 slots, four SO-DIMM slots, and six SATA ports all manage to find a home on a tiny motherboard. 

The feature set it brings to the table on such a small platform is impressive. However, that creativity will fetch a premium price. Currently selling for $399 on Newegg.com, it places the X299E-ITX/ac in the high-end segment as X299 motherboards currently top out at $499+ and have a floor of $209. Pricewise, this places it in the crosshairs of the GIGABYTE X299 AORUS Gaming 7 ($399), ASRock X299 Gaming i9 Professional ($389), MSI X299 Gaming M7 ACK ($379), and the ASUS ROG Strix X299-XE Gaming ($369). Most of those boards have three M.2 slots and six or more SATA ports, however, it would be near impossible to shoehorn an ATX sized board in a SFF case - heavy modifications notwithstanding. In the MicroATX world, the EVGA Micro is $289 with only one M.2 slot, while the dual M.2 slot MSI offerings are still to be released in North America. In other words, there isn't competition in the space as there are not any other boards this size currently found on the market. 

One of the main concerns about going to such a small motherboard is the loss of certain features to which the X299 platform provide. In previous HEDT mini-ITX motherboards, for example, users were limited to two memory modules and dual-channel operation, as seen in our review of the X99E-ITX/ac a couple of years ago. For this board, ASRock has put SO-DIMM memory on instead, offering quad-channel DDR4-4000 support up to 64 GB. This isn't the full 128 GB of most X299 boards paired with Skylake-X processors, but does give full bandwidth.

The other element of loss is on PCIe. For chips that have 28 or 44 PCIe lanes, having only one PCIe x16 slot is a bit of a kicker. To that end, ASRock has placed three M.2 slots on the board, and the X299E-ITX/ac comes with one reinforced full-length PCIe slot at x16. There are bifurcation options in the BIOS if a user has a riser card that can split the slot into dual x8/x8, though this feature was untested in the review. This makes much more use of the PCIe lanes than one would have normally expected.

On the network side, the board has a 2x2 802.11ac Intel AC 8265 card with wireless speeds to 867 Mbps. Additionally, there are two Intel NICs, an I219-V and I211-AT, for wired traffic. On the back panel IO, USB consists of two USB 3.1 (10 Gbps) ports with one Type-C, and four USB 3.1 (5 Gbps) ports driven by ASMedia chips. Adding to that, on the riser card is are a USB 2.0 header and USB 3.1 (5 Gbps) header managed by the chipset. Finally, audio functionality is carried out by the high-end Realtek ALC1220 codec. 

Connectivity wise, while the board is has a lot of features, that doesn't go to say there aren't some missing. Front panel USB 3.1 (10 Gbps) support isn't here, nor is the ability to use more than 64GB of memory. Granted, most users do not need it, but the option just isn't there. Six SATA ports can be a limitation for storage heavy users who haven't moved on to M.2, but I'd imagine those who use more than six SATA ports and three M.2 drives are rare in the consumer segment. Overall, the real estate appears to have been used wisely on this densely packed board. 

In the realm of performance, the board happily trudged through our testing without batting an eye. Multi-core performance was a bit slower than the rest, but this is due to how the board deals with the number of cores and its frequency. Turning MCE on was a different story as it happily turned up all cores to 4.5 GHz and went through the testing suite. The power delivery heatsink was without a doubt warmer than any I have checked while testing X299 motherboards at stock. When overclocking and testing, it was hot to the touch. If the plan is to push a high-power CPU to high overclocks on this tiny board, I would suggest a well-ventilated case or spot cooling on that VRM to keep temperatures low. 

For our ITX system, a special thanks goes out to GSkill who provided us with new high-speed DDR4 SO-DIMMs. The set they gave us, F4-3800C18Q-32GRS, is not currently found on the website. The 4x8GB kit is rated to DDR4-3800 @ CL18-18-18-38 with 1.35V and supports Intel's XMP 2.0 profiles. 

ASRock's Previous Mini-ITX HEDT

ASRock's previous mini-ITX high-end desktop board, the X99E-ITX/ac, was the first version of this design. It used the 'narrow ILM' version of the LGA2011-3 socket, and due to the limited number of consumer coolers that support that design, they shipped samples with a Dynatron cooler to fit. With this new model however, they are using a full sized LGA2066 socket for normal coolers. That is going to help integrate this motherboard into the builds that need it.

Due to Intel's new Xeon strategy, there is actually no increase in thread support from the X99E-ITX/ac to the X299E-ITX/ac. On the older board, it supported the top end Xeon E5 v4 processors, which were available up to 18 cores, albeit at a $4115 list price. The X299E-ITX/ac only supports the Core i7 and Core i9 consumer Skylake-X processors, but these also go up to 18 cores. Except this time, there are four memory channels, not two.

ASRock's X299 Strategy

Historically, ASRock doesn't push the super-high price ranges that the other three motherboard manufacturers do, preferring to sit lower in the market at both the low and high prices in its stack. For high-end desktop platforms, this usually means they are the cheapest, and we see the motherboards for X299 from ASRock range from $200 up to around $400, or $423 for the XE version of the Professional Gaming i9.

ASRock's X299 Motherboard Lineup (11/29)
Amazon Newegg
X299 Extreme 4     $200
X299 Killer SLI/ac   $240 $230
X299 Gaming K6   $278 $260
X299 Taichi Review 10/31 $295 $300
X299 Taichi XE     $323
X299 OC Formula     $400
X299 Professional Gaming i9 Review 9/26 $475^ $400
X299 Professional Gaming i9 XE     $423
X299E-ITX/ac [this review] $510^ $400

^ = sold by 3rd party

Information on Intel's X299 and our other Reviews

With Intel's release of the Basin Falls platform, encompassing the new X299 chipset and LGA2066 socket, a new generation of CPUs called Skylake-X and Kaby Lake-X were also released. The Skylake-X CPUs range from the 7800X, a hex-core part, all the way up to an 18-core 7980XE multitasking behemoth. Between the bookend CPUs are five others increasing in core count, as in the table below. The latter HCC models are set to be launched over 2H of 2017. 

Skylake-X Processors
  7800X 7820X 7900X   7920X 7940X 7960X 7980XE
Silicon LCC   HCC
Cores / Threads 6/12 8/16 10/20   12/24 14/28 16/32 18/36
Base Clock / GHz 3.5 3.6 3.3   2.9 3.1 2.8 2.6
Turbo Clock / GHz 4.0 4.3 4.3   4.3 4.3 4.3 4.2
Turbo Max Clock N/A 4.5 4.5   4.4 4.4 4.4 4.4
L3 1.375 MB/core   1.375 MB/core
PCIe Lanes 28 44   44
Memory Channels 4   4
Memory Freq DDR4 2400 2666   2666
TDP 140W   140W 165W
Price $389 $599 $999   $1199 $1399 $1699 $1999

Board partners have launched dozens of motherboards on this platform already, several of which we will have an opportunity to look over in the coming weeks and months. This specific review will cover the ASRock X299E-ITX/ac. 

Other AnandTech Reviews for Intel’s Basin Falls CPUs and X299

As we are in the process of testing more and more motherboards, some of the benchmark results in this review will contain numbers from motherboards we have not published a full review yet. Here's our current list of motherboards on the go, as well as some of our CPU reviews:

  • The Intel Skylake-X Review: Core i9-7980XE and Core i9-7960X Tested
  • The Intel Skylake-X Review: Core i9-7900X, i7-7820X and i7-7800X Tested
  • The Intel Kaby Lake-X Review: Core i7-7740X and i5-7640X Tested
  • Intel Announces Basin Falls: The New High-End Desktop Platform and X299 Chipset
  • ($400) The ASRock X299E-ITX/ac Review (this review) 
  • ($390) The ASRock X299 Professional Gaming i9 Review: [link
  • ($360) The MSI X299 Gaming Pro Carbon Review [link
  • ($300) The MSI X299 Tomahawk Arctic Review [link]
  • ($289) The ASRock X299 Taichi Review [link]
  • ($260) The MSI X299 SLI Plus Review [link]
  • ($500) The GIGABYTE X299 Gaming 9 Review (planned) 
  • ($400) The GIGABYTE X299 Gaming 7 Review (planned)
  • ($350) The ASUS Strix X299-E Gaming Review (being tested) 
  • ($337) The ASUS X299 TUF Mark 1 Review (being tested) 
  • ($330) The EVGA X299 FTW-K (arrived)
  • ($290) The EVGA X299 Micro (arrived)
  • ($?) The EVGA X299 Dark (planned)

To read specifically about the X299 chip/platform and the specifications therein, our deep dive into what it is can be found at this link.

X299 Motherboard Review Notice

If you’ve been following the minutiae of the saga of X299 motherboards, you might have heard some issues regarding power delivery, overclocking, and the ability to cool these processors down given the power consumption. In a nutshell, it comes down to this:

  • Skylake-X consumes a lot of power at peak (150W+),
  • The thermal interface inside the CPU doesn’t do much requiring a powerful CPU cooler,
  • Some motherboard vendors apply Multi-Core Turbo which raises the power consumption and voltage, exacerbating the issue
  • The VRMs have to deal with more power, and due to losses, raise in temperature
  • Some motherboards do not have sufficient VRM cooling without an active cooler
  • This causes the CPU to declock or hit thermal power states as to not degrade components
  • This causes a performance drop, and overclocked systems are affected even more than usual

There has been some excellent work done by Igor Wallossek over at Tom’s Hardware, with thermal probes, thermal cameras, and performance analysis. The bottom line is that motherboard vendors need to be careful when it comes to default settings (if MCT is enabled by default) and provide sufficient VRM cooling in all scenarios – either larger and heavier heatsinks or moving back to active cooling.

This means there are going to be some X299 boards that perform normally, and some that underperform based on BIOS versions or design decisions. We are in the process of quantifying exactly how to represent this outside of basic benchmarking, so stay tuned. In the meantime, take a look at the next motherboard for review. 

Visual Inspection
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  • dgingeri - Monday, December 4, 2017 - link

    Of course there are compromises. The processor has 44 PCIe lanes, and only 16 are able to be used thanks to there only being one slot. Even with the riser card and the M.2 slots, there are still compromises with this.
  • Samus - Monday, December 4, 2017 - link

    I've had the ASRock X99 ITX for two years. The sole compromise is literally one PCIe x16 slot, which is all 95% of people in the market for this board need. If you need more, you go ATX. Nobody is building ITX systems with SLI or mining in mind. Nobody. With the exception of maybe one SFX PSU, they can't even drive more than one high end videocard with a platform like this, and if you are using a case that holds an ATX PSU, why are you even considering an ITX board? The whole point of the system is to be compact.

    In other worse, this X299 follow-up is simply amazing. 9 native storage device ports on an ITX board is unheard of. Many ITX boards still have just 4 SATA ports (which, again, is all most people in the market for an ITX system are looking for since most cases will lack more than 4 storage bays.)
  • Gadgety - Monday, December 4, 2017 - link

    "If you need more, you go ATX."

    Well, yes and no. I know there are users who have used the x99 with bifurcation, in those 5%. I'd like a small pc in with a top of the line gpu and need a pci-e x1 for an additional feature. The trend for small PCs certainly seems to be growing, so offering additional pci-e possiblities on small M-ITX would be nice, whether through official bifurcation possibilities or other means. I checked the potential to using an M.2 port for a pci-e card, but couldn't find an adapter.
  • Vatharian - Monday, December 4, 2017 - link

    I am so sad that DTX didn't took off. Just a tiny little bit of real estate, most of cases already have two slots for wide GPUs, and so much more options. If this board been DTX with 2x 16x ports, Titan Xp SLI would have been possible out of the box (albeit with water cooling, of course). Or stuff powerful storage controller in one and decent 10G or 40G network card in the other port. Or stuff really anything int he other slot.
  • Gigaplex - Monday, December 4, 2017 - link

    There's always micro ATX. It's not that different to DTX.
  • Actae0n - Monday, December 4, 2017 - link

    You certainly raise a good point. However, there are some cases, such as the Fractal Design Nano S (pretty sweet case, I might add), that only support Mini-ITX and can hold an ATX PSU.
  • dgingeri - Monday, December 4, 2017 - link

    It was not my point that it didn't have a use, but rather that the article is titled "The ASRock X299E-ITX/ac Motherboard Review: An 18-core No-Compromise Mini-ITX" when in fact there is a compromise in order to get to the form factor. I don't like people stating "no compromise" when in fact there is compromise in something.
  • tim851 - Monday, December 4, 2017 - link

    The single PCI-E x16 slot is not a compromise, it's A FEATURE. That's what you buy an ITX board for.
  • Mr Perfect - Monday, December 4, 2017 - link

    Yeah, calling out ITX for only having one PCIe slot is kind of missing the point of ITX.
  • mnoi - Wednesday, December 6, 2017 - link

    I agree, the two usb-c ports should have been thunderbolt enabled at the very least.

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