ASUS ROG STRIX Z370-I Gaming Motherboard Review

ASUS dominates the mini-ITX market with its various "I" series motherboards. It proved that going to a smaller form factor didn’t mean compromising on performance, only expandability. Even then, ASUS has mitigated a lot of those limitations as well. Does the ASUS ROG STRIX Z370-I Gaming motherboard live up to its predecessors.


Subsystem Testing

NOTE: For all subsystem testing, an Intel Core i5 8600K (3.6GHz / 4.3GHz Turbo) and 2x 8GB (16GB total) Kingston HyperX (3200MHz DDR4 18-19-19-39, 2T@1.35v) memory modules running at DDR4 2666MHz speeds (stock testing, up to 3200MHz overclocked) were used. For power, I used the an XFX XTR 850 watt unit. Our discreet graphics card needs were handled by an EVGA NVIDIA GeForce GTX 780Ti reference card. The CPU was cooled with a Koolance Exos 2.5 system and a Koolance CPU-390 waterblock.

Sound Hardware

ASUS chose the Realtek S1220A HD Audio CODEC for it’s SupremeFX 8-channel audio solution. This solution uses the same found on larger motherboards. The CODEC features EMI shielding, dual-OP amplifiers, Nichicon audio capacitors, and more. It features 120 dB SNR playback and 113 dB SNR recording capabilities.

The following specifications were taken from the manufacturer’s website:

SupremeFX 8-Channel High Definition Audio CODEC S1220A

- Dual Headphone Amplifiers

- Impedance sense for front and rear headphone outputs

- Supports : Jack-detection, Multi-streaming, Front Panel Jack-retasking

- High quality 120 dB SNR stereo playback output and 113 dB SNR recording input

- SupremeFX Shielding Technology

- Supports up to 32-Bit/192kHz playback

Audio Feature :

- Optical S/PDIF out port(s) at back panel

- Sonic Radar III

- Sonic Studio III

The audio solution offered excellent playback in all applications. The sound quality was as good as any other S1220A or similar CODECs I’ve tested.

Audio - Subjective Listening

For subjective listening, you want to listen to something that covers a range of sound types. For this portion of the review I went with Five Finger Death Punch’s American Capitalist CD.

CD audio worked as expected.

Audio - Microphone Port Testing

The onboard audio MIC-IN port was tested using a Logitech Internet Chat Headset. Spoken words were recorded from the Windows Sound Recorder found under the Accessories folder in the start menu within Windows. The recording was using the highest quality settings available in the control panel for the audio device being used to record.

With the microphone boost option disabled, playback of the sample had somewhat low audio levels. However, the sample was distortion free. With the microphone boost option enabled the audio sample had much higher audio levels as expected, and remained distortion free. Speaking strictly of recording capability, this is one of the better solutions I’ve ever worked with.

Gaming Audio Quality

I have done some light gaming testing on our motherboards to get a sense of how the audio performs in games and not just how they sound listening to music as these are far more different activities than one might imagine. Due to the ease in which I can simply copy the game over the network without properly installing it, I have selected EA/BioWare’s Knights of the Old Republic MMO. No matter how you feel about this game, or games of this type, one area it does well is with its audio. There aren’t a lot of options to configure in the game for this, so these settings remain "apples to apples" for all the systems that we test. Additionally, the iconic Star Wars music is part of the game’s sound track and its various themes can be heard in the game world. This is music that many people grew up with. Having watched the movies more times than could easily be counted, you end up with a sense for how these songs and sound effects should sound. I think this allows for ease of comparison on different platforms and from different sources.

In game audio playback was fantastic. All the familiar Star Wars sounds sounded correct, I never experienced audio related abnormalities or unexpected results from the audio solution. All the audio seemed rich and full.

DPC Latency

Deferred procedure call latency or DPC testing is something that we’ve been asked about and this is the first article we’ve done which integrates that type of testing. For those who may not know what DPC is I’ll explain. Deferred procedure calls are a function within Windows that allows higher priority tasks such as device drivers to defer lower priority tasks for execution at later times. It’s an interrupt and reassignment of sorts performed by the operating system.

DPC latency varies from board model to model and brand to brand. DPC issues show up in the form of audio dropouts and streaming video issues. Naturally this is something that the enthusiast would want to avoid. Fortunately, there is a nice tool for checking this which doesn’t even require and installer. I used the LatencyMon and let it run for 10 minutes to graph the results.

I thought it necessary to look at some systems which I wouldn’t have suspected of having any DPC latency issues around my house to get some baseline numbers for comparison. The utility graphs out the data nicely and tells you what your latency results mean in terms of the real-world problems you might encounter with the current system configuration. I went with my own personal machine which uses the ASUS Rampage V Extreme’s onboard audio and Windows 10.

ASUS ROG Rampage V Extreme

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Our baseline system shows a reported interrupt to process latency of 225 and the highest reported DPC routine execution time was 262. This means that you shouldn’t experience any drop out issues with audio or video on this system.


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In this test, we saw a reported interrupt to process latency of 63. The highest reported DPC routine execution time was 359. The DPC latencies covers a range that was broader than our control system. However, this broad ranges still within the acceptable margin for audio playback. You shouldn’t experience dropouts or any other problems with this audio solution.

Drive Performance

SSD Testing

For our testing, the operating system is always installed to a Samsung 840 Pro SATA based SSD using the controller in AHCI or RAID modes as required. In certain specific circumstances an Intel SSD 750 400GBdrive is used in a U.2 configuration for our operating system installation. Often this is used to verify NVMe boot capability or to circumvent issues installing to a standard SATA drive with AMD X370 chipset based motherboards. M.2 functionality is tested using a Corsair MP500 240GB drive for standalone M.2 testing. A second, identical drive is employed for testing RAID0 performance on motherboards that support this functionality natively, without PCIe adapter kits. This is a PCIe based SSD drive supporting the NVMe protocol.

USB 2.0 Testing

To test the capabilities of the onboard USB 2.0 connections, we used a Sans Digital external eSATA / USB 2.0 drive enclosure, connected via the USB 2.0 port. Installed in the enclosure are dual Western Digital Caviar Black WD1002FAEX drives in a RAID0 configuration. In theory, this should always saturate the USB 2.0 connection an isolate the motherboard as the biggest variable in our USB 2.0 performance tests.

USB 3.x Testing

Standard SATA III 6Gb/s drive tests were performed using Western Digital Caviar Black WD1002FAEX hard drives on all SATA headers. The SATA drives were used for testing in RAID 0 16k block size configurations on all applicable controllers when possible. Frequently, third party or AMD based RAID controllers cannot always be configured the same as Intel controllers can. Testing was also conducted using the same model SATA drives in a stand-alone SATA configuration on all applicable controllers. All drive benchmarks were done using the freely available CrystalDiskMark program, run with both 50MB and 100MB sized test sets.

Given that motherboards are now supporting UASP and various USB 3.0 boost methods on many models, we’ve updated our testing methodology to include a UASP test whenever possible. The USB 3.0 implementation that some manufacturers are using does allow for a performance boost with non-UASP compliant hardware as you’ll see using what these companies call "turbo" mode. Granted the difference isn’t as pronounced as it is when enabling UASP on a device that supports it. The USB 3.0 Flash drive tests are essentially the same as these have always been since we started doing these tests, but with the added turbo mode test to showcase the feature in action. The USB 3.0 SSD UASP Enabled / Disabled tests are utilizing a Corsair Force GT 60GB SATA 3 SSD plugged into a Thermaltake BlacX 5G docking port which uses a USB 3.0 connection. This device was selected due to having UASP compatible firmware. At present, we are not conducting USB 3.1 testing due to the poor availability of such devices at the time of this writing.

Mini-ITX motherboards are quite basic it comes to their storage configuration. A lack of PCB real estate means a lack of third-party controllers, USB hubs and excessive M.2, U.2, and SATA ports. While the Z370 Express chipset supports up to 6x SATA III 6Gb/s ports, the ROG STRIX Z370-I Gaming motherboard provides only four. These are vertical, rather than right angled ports. I normally despise vertical ports, but these typically work better in mini-ITX cases. There are two M.2 slots, one of which accepts SATA or PCIe devices while the other is PCIe only.

USB is straight forward as well with 6x USB 3.1 Gen 1 ports provided by the Intel chipset along with 6x USB 2.0 ports. A single ASMedia controller provides USB 3.1 front panel connectivity.

RAID Support

Intel RAID support is very robust allowing for a huge range of strip sizes from 8k to 128k. RAID levels 0, 1, 10, and 5 are all supported as well. Intel’s RAID BIOS is unchanged from previous generations and worked flawlessly here. Chipset based, rather than CPU based NVMe RAID arrays are possible. VROC doesn’t work on non-HEDT platforms as they have insufficient PCIe lane allocation for that. However, Optane memory technology is supported here.

50MB Test Set

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In the 50MB sequential read test we see the RAID 0 controller deliver 394MB/s compared to 445MB/s in AHCI mode. USB 3.0 gave us a result of 307MB/s, which is on the lower side of the spectrum. What is very odd is that the USB 2.0 numbers are higher than I’ve ever seen them at 44MB/s. In the 50MB sequential write test, we are primarily limited by the write speeds of the devices and not the bus. We see a result of 212MB/s for the RAID 0 configuration and 123MB/s for the AHCI. USB 3.0 was again within the ballpark we predicted. However, USB 2.0 results were still higher than expected at 42MB/s instead of something like 37MB/s. It’s not a huge difference, mind you, but worth noting.

100MB Test Set

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The 100MB sequential read test, we see a result of 352MB/s in the RAID 0 test and 220MB/s using the AHCI configuration. USB 3.0 continued to be predictable while USB 2.0 continued to be well beyond what we normally see. In the 100MB sequential write test, we saw a result of 248MB/s in the RAID 0 test and 129MB/s in the AHCI test. USB 3.0 performance was the roughly expected 85MB/s. USB 2.0 performance was again higher than anticipated at 42MB/s.

M.2 / U.2 NVMe Test Set

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Read test performance metrics were as follows: 2775MB/s (50MB), 2561MB/s (100MB), and 2775MB/s (1000MB). In the write tests, we saw the following performance results: 1487MB/s (50MB), 1404MB/s (100MB), and 1489MB/s (1000MB).

M.2 / U.2 NVMe RAID Test Set

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Read test performance metrics were as follows: 3684MB/s (50MB), 3321MB/s (100MB), and 3690MB/s (1000MB). In the write tests, we saw the following performance results: 2777MB/s (50MB), 2779MB/s (100MB), and 2787MB/s (1000MB).

M.2 performance was about what I expected. As usual, the tests falter a bit in one particular test. It seems to be the 100MB/s test set more often than not.

Network Utilization Tests

LAN Speed Test software was used with Windows Task Manager to determine the performance levels of the onboard network interface. LAN Speed Test was used to measure bandwidth and transfer speeds, while Windows Task Manager monitored CPU utilization on the test system. For the testing, an 800MB file test was used with the default packet configuration for the application. The test was run three times with the middle result chosen. Results were captured for the low, medium and high transfer rates. The test was performed using a plenum rated category 5e crossover cable to bypass any traffic, routing or other transfer issues and possible packet loss or corruption that can be caused by a router/switch or hub. The cables were connected between two test machines, one using the onboard NIC(s) of the board being reviewed and the other is an Intel EXPI9400PT 10/100/1000Mbps PCI-Express Gigabit Ethernet adapter.

Wireless network testing, if applicable was performed using a connection to an 802.11/AC enabled wireless router. ASUS model RTAC56U and then sent to a test machine connected to the same router via a RJ-45 LAN connection. The target system network adapter is a Intel EXPI9400PT 10/100/1000Mbps PCI-Express Gigabit Ethernet card. The network settings for both network controllers and the router are all at their defaults and the 802.11/AC router has no other devices connected to it.

Wired Networking

As expected, ASUS went with the i219v Gigabit controller. It is capable of 10/100/1000Mbit speeds.

LAN1 (Intel i219v)

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The average transfer rate in the write or upload test was 46.70MB/s. In the read or download test, the average transfer rate was 68.67MB/s. In the write or upload test, the maximum transfer rate was 50.08MB/s. In the read or download test, the maximum throughput was 71.46MB/s. In contrast, the minimum transfer speeds were 39.08MB/s (write) and 64.50Mb/s (read). CPU usage was 5% in the write test and 3% in the read test.

Wireless Networking

ASUS integrated a wireless controller into the ROG STRIX Z370-I Gaming. It is capable of 802.11a/b/g/n/ac speeds. It supports dual band 2.4GHz / 5.0GHz and MU-MIMO,


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In the write or upload test, the average transfer rate was 8.55MB/s. In the download or read test, the average transfer rate was 7.29MB/s. In the write test we saw a maximum throughput of 8.61MB/s and 7.90MB/s in the download or read test. In the write or upload test, our minimum transfer rate was 8.47MB/s. In the read test we saw a minimum of 6.84MB/s. CPU usage in the write test was 3% and 4% in the download test.

I had no trouble connecting at "866Mbits" per second according to Windows. My router was set to 802.11ac with no compatibility mode. Still, the performance was lacking as you can see. I tried using an Ad-Hoc connection to another system which didn’t work at all.

Benchmark Test Systems

Note: We have changed up our benchmarks somewhat. Our testing standards are shifting, so some results won’t be directly comparable, and we only have a couple of data points for newer benchmarks.

The following system configurations were used for the Sandra memory benchmark graph, as well as all graphs listed under the Application and Gaming Benchmarks sections:

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SiSoft Sandra

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Note that all results above were obtained running the installed memory in dual-channel or quad-channel memory modes where applicable.

In this test, we see a solid result for the ASUS ROG STRIX Z370-I Gaming, however it doesn’t take the top spot here by any means.

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In the Sandra CPU test, we see the ASUS ROG STRIX Z370-I Gaming fall behind the other test systems by a small margin.

Hyper Pi

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However, in this test the ASUS ROG STRIX Z370-I Gaming turns in the best score out of all our test systems.


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Once again, the ASUS ROG STRIX Z370-I Gaming turns in an excellent score and edges out the other systems.