The ASRock X399 Phantom Gaming 6 Motherboard Review: $250 Sixteen Core Stunner

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 the manufacturing process and prowess, so these are tested.

For 2019, we are running an updated version of our test suite, including OS and CPU cooler. This has some effect on our results.

For this review, we had to test with a 2950X as the 1950X we normally use with X399 had to be returned. This has some effect on benchmark data, however it is still rated to the same 180W TDP as the 1950X.

Power Consumption

Power consumption was tested on the system while in a single ASUS GTX 980 GPU configuration with a wall meter connected to the Thermaltake 1200W power supply. This power supply has ~75% efficiency > 50W, and 90%+ efficiency at 250W, 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.

Power draw on the ASRock X399 Phantom Gaming 6 isn't too far away from the competition at full load with a total power draw on our test suite of 274 W. At long idle and idle power stages however, the slight reduction in controllers and features onboard could be at play with the lowest X399 power results attained so far.

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 starts loading. (We discount Windows loading as it is highly variable given Windows specific features.)

When compared directly against boards such as the ASRock X399 Taichi, the ASRock X399 Phantom Gaming 6 in POST did suffer somewhat with some of the worst results so far. Only the MSI MEG X399 Creation has performed worse so far and while the Phantom Gaming 6 was noticeably better than this, it's still off the mark we expect.

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.

All of the X399 motherboards on test haven't had manual DPC optimizations out of the box, but the ASRock X399 Phantom Gaming 6 managed to achieve the best latency result by a decent margin over boards such as the ASUS X399 ROG Zenith Extreme and the ASRock X399 Taichi.