ASRock X99E-ITX/ac Motherboard Review


ASRock announced its exclusive mini-ITX coverage for the LGA 2011-v3 platform with much praise and panning from the enthusiast community, a large portion of which didn’t see the point of pairing a 40-lane (or 28-lane) PCIe 3.0 controller with a single expansion slot. Among those who understood its usefulness, there were still those who felt that two memory slots might be a little too limiting for the CPU’s quad-channel controller. But if we look at this another way, we see an LGA 1150 alternative with up to twice as many active cores. And that can only be a good thing, right?

A quick look at the overall picture shows a board with all the high-end mini-ITX prerequisites, from dual gigabit Ethernet controllers to a true dual-band 802.11ac (867 Mb/s) controller with integrated Bluetooth, which we as PC enthusiasts know is far more than an interface for your hands-free kit. It even has an eSATA port. But what’s with the two teal USB ports? ASRock found a use for a couple of the chipset’s spare PCIe 2.0 lanes, adding ASMedia's ASM1142 USB 3.1 controller. Two more lanes connect the PCIe portion of the SATA Express connector, leaving a few lanes untapped to reduce DMI bandwidth.

The CPU’s leftover PCIe 3.0 lanes aren’t completely wasted either, as the X99E-ITX/ac connects four of them to an M.2 slot. The trip gets a little stranger at this point because, according to Device Manager in Windows, the secondary network controller is connected to the CPU’s PCIe 3.0 pathway. We’ve heard that Haswell-E processors can support up to five devices, and connecting this to the CPU does free up some of the chipset’s DMI bandwidth, even though the network controller doesn’t benefit from PCIe 3.0.

Before we dig any deeper into the details, here’s how the X99E-ITX/ac compares to the microATX motherboards we’ve reviewed:

Technical Specifications

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The mini-ITX board has fewer slots of course, and adds a USB 3.1 controller, but...well, did you notice this page's title? It seems that while everyone was talking about the transition of mini-ITX to performance platforms (2007), AMD was pushing DTX as a means to standardize the SFF–type gaming machine. That’s “Shuttle” form factor. Its main benefit over mini-ITX was a 9.6” front-to-back measurement, the same as a microATX motherboard, which meant that it had space for four DIMMs. Our benchmarks will show whether the missing memory channels are a real problem or a mere distraction.

X99E-ITX/ac Details

The X99E-ITX/ac’s greatest design weakness may be those four pins at the leading edge of the PCIe x16 connector, according to my colleagues. It’s a fan header, and the connectors of some fans won’t fit under some graphics cards. Mine fit, but it did smash the wires flat against the top of the plastic, and there’s always a chance that their fan plugs were taller than mine. It’s also one of three connectors though, where many mini-ITX boards only have two.

My biggest concern instead is the rectangular "narrow ILM" cooler mount, which is an alternative specification previously defined for tightly-spaced multi-socket server boards. Where will we find a cooler?

That’s right, ASRock actually includes a cooler with the X99E-ITX/ac! Designed for 2U servers, this little thing is pretty amazing, beginning with its specs. Dynatron says its 60x28mm fan produces 47.5 decibels at 7000 RPM, but our measurements show that it spins all the way up to 7500 RPM, producing a whopping 54 decibels in the process. Thankfully, non-overclockers don’t need to worry about it generating much more than 33 decibels as long as they don’t run an extended full load. And since heavy workloads are the reason you bought an X99 platform for your mini-ITX case, ASRock also includes a liquid cooler mounting bracket for Cooler Master’s Seidon 120V. Other readily-available upgrades include Dynatron’s R27, which is an 80mm alternative to the included cooler. Cooler Master may be the real winner here.

Accessing the M.2 connector immediately adjacent to the CPU socket requires a narrow CPU cooler. We found several big-air coolers that provide enough clearance, but can’t be screwed down due to the unusual mounting pattern. The USB 3.0 header just south of the M.2 mounting screws would provide even more heat sink clearance, if only more cooling options were available to take advantage of the space.

Shown in the motherboard images, the X99E-ITX/ac includes a separately-wrapped mini-PCIe Wi-Fi card in addition to the parts shown. The installation kit’s greatest weakness might be its inclusion of only two SATA cables, though a USB 3.0 to USB 2.0 adapter points to the motherboard’s single USB 2.0 header in a market where more than two ports are often needed.

Firmware And Software

ASRock App Shop includes a software updater in addition to freeware links. Previous troubles linking to the update server appear to have been resolved.

ASRock’s A-Tuning interface hasn’t changed from our recent deep-dive, including useful integrated utilities like XFast RAM, XFast LAN and USB Key. The software is tied to firmware settings and limits though, and the X99E-ITX/ac has only one factory-programed overclocking profile at 3.8GHz/1.20V CPU core.

ASRock’s Auto-Tuning program provides 4.3GHz at 1.25V, which is stable within the limits of thermal throttling (occurring after several minutes at full load). Manual tuning provides frequency and voltage controls within the full range supported by hardware.

The reason A-Tuning finds only one overclocking profile is because it pulls this information from firmware. The setting is a good starting point for basic overclocking, though it’s slower than the “Load 4GHz and XMP OC Setting” that accompanies our installation of DDR4-3000.

The long story on this is that since XMP-3000 requires a 125MHz base clock, the “4GHz and XMP” setting drops the operational multiplier to 32x and the CPU Cache Ratio to 24x, while increasing the CPU core voltage to 1.20V and CPU base clock ratio to 1.25x. Four gigahertz is faster than 3.8, and it’s the same voltage, so everybody wins.

Additional tuning gets us to 4.3GHz at 43x 100MHz. Our processor's usual 4.45GHz overclock works for a while, but the 1.28V needed to get it there eventually causes thermal throttling.

I was nearly thrilled to see the range of functioning memory ratios in the X99E-ITX/ac, all the way up to DDR4-2800 at 14x. DDR4-3000 at 15x doesn’t work, but DDR4-3200 at 12x works by using a 4:3 memory controller-to-CPU core ratio. That leaves our DDR4-3000 the odd man out by requiring a 125MHz BCLK at the 4:3 memory controller ratio and 9x memory multiplier. Oh, and for those who forgot, a doubled data rate is 2x the set clock frequency.

Thermal throttling ruined our attempts to find a completely stable overclock at 1.28V CPU core, so we chose 1.225V after lengthy experimentation. That still got us within 150MHz of this CPU's previous 1.28V maximum clock, so efficiency seekers would probably be wise to use the lower voltage anyway.

A separate voltage menu includes a redundant DIMM voltage setting, in addition to “Load-Line Calibration” to control core voltage drop under load, I/O voltage and PCH (chipset) voltage.

How We Test

Hardware and software settings carried over from our initial round-up allow me to compare the performance of every tested X99 motherboard to the most recent products. Charts include the three most closely-sized competitors:


Synthetic Benchmarks

Synthetic benchmarks are a great way to find configuration problems like unrequested overclocks (which wreck a head-to-head match) and configuration issues (which can slow down certain components). In this case, we can see that the X99E-ITX/ac’s 3DMark 11 scores suffer slightly compared to larger motherboards, but we don’t see the cause until we get towards the end of our synthetic test.

Scrolling through to the sixth image, we see a 36% performance deficit in Sandra's Cryptography module, and the next image reveals the reason: the X99E-ITX/ac interfaces only two of the platform’s four memory channels. Bandwidth drops by slightly less than half, but will we see any big differences in real-world applications?

Gaming Benchmarks

Here’s a shocker: the X99E-ITX/ac performs better in most games than its larger microATX rivals. Tighter default timings are most likely reason for this odd behavior, as more DIMMs mean more latency.

We were particularly interested in seeing how Grid 2 worked at low settings, since this game has responded poorly in the past to either low bandwidth or high latency. The bandwidth issue seemed to evaporate at lower data rates in our DDR3 platform tests though, and similar timings between dual- and quad-channel boards allowed the one with the least total latency (two channels) to assume leadership in this title.

Before you go out and ditch half your RAM, we’d like to remind everyone that the gaming differences seen in the charts are too small to notice in real-world game play.

Application Benchmarks

Though the X99E-ITX/ac did suffer a small loss in Photoshop's OpenCL-optimized filters and took a small lead in Adobe Premiere, its overall performance appears average.

We do need to reveal a trick though: we had to change the memory to get a decent time in Adobe After Effects. The reason is that this benchmark needs more than 8GB of RAM, and our modules are 4GB each. By using the same RAM in both dual- and quad-channel tests, the dual-channel board suffers half the bandwidth and half the capacity. That's even less fair than different RAM, but if you want to know, the completion time for this test slowed from 20 seconds to 73 seconds when crippled by an 8GB capacity.

Power, Heat And Efficiency

With half as many memory channels, fewer slots and a voltage regulator that ASRock said is designed for better efficiency, the X99E-ITX/ac draws a little less power than its microATX rivals.

An overall performance deficit of less than one percent allows the X99E-ITX/ac’s reduced power to translate almost directly into increased efficiency.

Overclocking Performance

BIOS Frequency & Voltage Settings

The X99E-ITX/ac includes a similar range of settings compared to its larger siblings, lacking only a little PCH and DRAM voltage for the sake of compact system thermal limits. Yet, even those two reduced settings far exceed anything we’d need for safe-and-sane O/C evaluation.

As discussed in the firmware section of this review, thermal throttling forces the use of a lower CPU core voltage to retain a consistent O/C frequency. At 1.225V CPU core, the board still pushes our Core i7-5960X to 4.3GHz. This is also the first ASRock motherboard we’ve tested to exceed DDR4-3200, though we’re not sure how much of this feat is due to firmware advancement, and how much is due to the missing third and fourth DIMMs.

The DDR4-2666 test lets us see how different boards optimize timings for non-native data rates. The X99E-ITX/ac has only half the memory channels of its microATX competitors, yet still produces more than half the bandwidth.

Value Analysis

We usually try to put a motherboard up against its peers to determine the best value for the money, but that’s a problem for the only mini-ITX motherboard for LGA 2011-v3. For better or worse, it has no peers. Based on a $250 MSRP, here’s how it compares to its closest rivals.

MicroATX might be a better value, and this is where we’d normally discuss features versus price. Indeed, the X99E-ITX/ac comes with a $30 CPU cooler where the microATX motherboard do not, and has USB 3.1. The X99E-ITX/ac also requires a special CPU cooler though, and your few cooler upgrade options appear slightly overpriced for the money. Moreover, the included cooler’s tiny 60mm/7500 RPM fan will drive you nuts if you like to push a lot heat from your processor. This might be a good time to pine for AMD’s DTX form factor, which would have allowed space for a standard CPU cooler mechanism and four DIMMs. Unfortunately, VIA's mini-ITX won that competition by being first out of the gate.


We saw the huge bandwidth penalty of having only two DIMM slots on a four-channel memory controller, but we also saw how little effect that bandwidth reduction had on real-world applications. The X99E-ITX/ac even won some gaming benchmarks, though we probably could have gotten similar results by dropping any competing samples to a pair of DIMMs.

The biggest deficit of mini-ITX is indeed cooling, as we were forced to use lower core voltage to reach a non-throttled overclock that was about 150MHz lower than what we've seen from larger boards. But we might have been tempted to use lower voltage anyway to improve efficiency in a compact PC.

That brings us to the award discussion. Since the X99E-ITX/ac exceeded our expectations, we could give it our ordinary “Approved” recognition. Since it doesn’t have anything to compete directly against, it can’t win our comparative value “Recommended” award. Our top award, “Choice”, means that a product is best-in-class. There are no other motherboards directly competing with ASRock's X99-based mini-ITX offering. But even if there were, there's a good chance this would be our victor anyway. An impressive list of features (despite limited board space), performance  befitting a workstation-class platform and a reasonable price tag earn the X99E-ITX/ac the highest honor we bestow.

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