The NZXT N7 Z370 Motherboard Review: A New Player in the Motherboard Market

System Performance

Not all motherboards are created equal. On the face of it, they should all perform the same and differ only in the functionality they provide - however, this is not the case. The obvious pointers are power consumption, but also the ability for the manufacturer to optimize USB speed, audio quality (based on audio codec), POST time and latency. This can come down to manufacturing process and prowess, so these are tested.

Power Consumption

Power consumption was tested on the system while in a single GPU configuration with a wall meter connected to the Corsair HX 750 power supply. This power supply is Platinum rated. As I am in the US on a 120 V supply, leads to ~87% efficiency > 75W, and 92%+ efficiency at 375W, suitable for both idle and multi-GPU loading. This method of power reading allows us to compare the power management of the UEFI and the board to supply components with power under load, and includes typical PSU losses due to efficiency. These are the real world values that consumers may expect from a typical system (minus the monitor) using this motherboard.

While this method for power measurement may not be ideal, and you feel these numbers are not representative due to the high wattage power supply being used (we use the same PSU to remain consistent over a series of reviews, and the fact that some boards on our test bed get tested with three or four high powered GPUs), the important point to take away is the relationship between the numbers. These boards are all under the same conditions, and thus the differences between them should be easy to spot.

In our power consumption testing, it's pretty obvious to see the i7-8700K uses a fair amount less power compared to the i9-7900X. The i7-8700K is a 95W TDP chip while the deca-core i9-7900X is a 140W chip. In theory, on load, these should be around 45W apart assuming the same exact system and parameters give or take several Watts for reading accuracy. The 8700K idles at a mere 45W while in the OS which is a fair amount less than the 7900X systems we have tested. The 8700K showed 145W use at the wall in load testing which was closer than I expected to the EVGA results. That said, the EVGA CPU did run at base frequencies in the test where others sat at the multi-core turbo value (3.6 GHz), hence that difference. 

Non-UEFI POST Time

Different motherboards have different POST sequences before an operating system is initialized. A lot of this is dependent on the board itself, and POST boot time is determined by the controllers on board (and the sequence of how those extras are organized). As part of our testing, we look at the POST Boot Time using a stopwatch. This is the time from pressing the ON button on the computer to when Windows 10 starts loading. (We discount Windows loading as it is highly variable given Windows specific features.

POST times for the NZXT N7 board took 30 seconds on default and 28.7 seconds when stripped. This value has it towards the bottom of the pack. Worthwhile to note here is the system had trouble getting a signal to my monitor in a similar timely fashion as the other motherboards so the timing could be a couple of seconds off from where I normally stop the clock. 

Rightmark Audio Analyzer 6.2.5

Rightmark:AA indicates how well the sound system is built and isolated from electrical interference (either internally or externally). For this test we connect the Line Out to the Line In using a short six inch 3.5mm to 3.5mm high-quality jack, turn the OS speaker volume to 100%, and run the Rightmark default test suite at 192 kHz, 24-bit. The OS is tuned to 192 kHz/24-bit input and output, and the Line-In volume is adjusted until we have the best RMAA value in the mini-pretest. We look specifically at the Dynamic Range of the audio codec used on board, as well as the Total Harmonic Distortion + Noise.

Due to circumstances currently out of our control, we were unable to get RMAA results for this board. The problem does not lie with the board itself. Once we are able to get it working properly, the space will be updated with data. 

DPC Latency

Deferred Procedure Call latency is a way in which Windows handles interrupt servicing. In order to wait for a processor to acknowledge the request, the system will queue all interrupt requests by priority. Critical interrupts will be handled as soon as possible, whereas lesser priority requests such as audio will be further down the line. If the audio device requires data, it will have to wait until the request is processed before the buffer is filled.

If the device drivers of higher priority components in a system are poorly implemented, this can cause delays in request scheduling and process time. This can lead to an empty audio buffer and characteristic audible pauses, pops and clicks. The DPC latency checker measures how much time is taken processing DPCs from driver invocation. The lower the value will result in better audio transfer at smaller buffer sizes. Results are measured in microseconds. 

Our DPC latency results were a bit of a surprise here with the N7 coming in last. I had to search our the latest chipset and ME drivers as well as manually search for the audio drivers and install each of them (NZXT did not include a driver disk and the webpage is not live to source them from it). That said, I plugged in a speaker and played a game and transferred some large files hoping to choke things up, but the sound didn't pop or click nor were there any audible pauses.