Board Features

The ASRock X399 Phantom Gaming 6 is an ATX motherboard and offers users an entry-level option at just $250 onto the Threadripper socket. Some of the major features on offer include triple M.2 which all support NVMe drives, and dual LAN capability with the inclusion of a Realtek 2.5 GbE RTL8125AG Gaming NIC, which is complemented by a second Intel I211AT NIC. All three of the full-length PCIe 3.0 x16 slots run at the full available bandwidth and offer support for three-way NVIDIA SLI and AMD CrossFire multi-graphics setups.

ASRock X399 Phantom Gaming 6 ATX Motherboard
Warranty Period 3 Years
Product Page Link
Price $250
Size ATX
CPU Interface TR4 / SP3r2
Chipset AMD X399
Memory Slots (DDR4) Eight DDR4
Supporting 128GB
Quad Channel
Up to DDR4-3400
Video Outputs N/A
Network Connectivity Realtek RTL8125AG (2.5 GigE)
Intel I-211AT Gigabit (1 GigE)
Onboard Audio Realtek ALC1220
PCIe Slots for Graphics (from CPU) 3 x PCIe 3.0 (x16)
PCIe Slots for Other (from PCH) N/A
Onboard SATA Eight, RAID 0/1/10
Onboard M.2 1 x PCIe 3.0 x4 (top slot) - 22110
1 x PCIe 3.0 x4 (left middle slot) - 2280
1 x PCIe 3.0 x4/SATA (right middle slot) - 2280
USB 3.1 (10 Gbps) 1 x Type-A
1 x Type-C
USB 3.0 (5 Gbps) 8 x Rear Panel (Type-A)
2 x Header (four ports)
USB 2.0 2 x Header (four ports)
Power Connectors 1 x 24-pin ATX
2 x 8-pin CPU
Fan Headers 1 x CPU (4-pin)
1 x CPU/Pump (4-pin)
3 x System (4-pin)
IO Panel 1 x USB 3.1 Type-A (USB 3.1 Gen 2)
1 x USB 3.1 Type-C (USB 3.1 Gen 2)
8 x USB 3.1 Type-A (USB 3.1 Gen 1)
1 x Network RJ-45 (Realtek)
1 x Network RJ-45 (Intel
5 x 3.5 mm Audio Jacks (Realtek)
1 x S/PDIF (Realtek)
1 x PS/2 Combo Port

On back panel is just two USB 3.1 G2 ports with a Type-A and Type-C both featured; a further eight USB 3.1 G1 Type-A ports make up the boards rear panel extensive USB block on the rear panel. While the cheapest board on the chipset usually contains a budget-focused controller set, the ASRock X399 Phantom Gaming 6 is different in that it’s just as premium as other options with a Realtek ALC1220 audio codec and dual LAN, except for limited support for just 180 W processors. This includes CPUs such as the Threadripper 2920X and 2950X CPUs.

Test Bed

As per our testing policy, we take a high-end CPU suitable for the motherboard that was released during the socket’s initial launch, and equip the system with a suitable amount of memory running at the processor maximum supported frequency. This is also typically run at JEDEC subtimings where possible.

It is noted that some users are not keen on this policy, stating that sometimes the maximum supported frequency is quite low, or faster memory is available at a similar price, or that the JEDEC speeds can be prohibitive for performance. While these comments make sense, ultimately very few users apply memory profiles (either XMP or other) as they require interaction with the BIOS, and most users will fall back on JEDEC supported speeds - this includes home users as well as industry who might want to shave off a cent or two from the cost or stay within the margins set by the manufacturer. Where possible, we will extend out testing to include faster memory modules either at the same time as the review or a later date.

Test Setup
Processor AMD Ryzen Threadripper 2950X,
16 Cores, 32 Threads, 3.5 GHz (4.4 GHz Turbo)
Motherboard ASRock X399 Phantom Gaming 6 (BIOS P1.10)
Cooling Thermaltake Floe Riing RGB 360
Power Supply Thermaltake Toughpower Grand 1200W Gold PSU
Memory 4x8GB GSkill TridentZ RGB DDR4-3200
Memory Settings DDR4-2666, 1.2 V, 16-18-18-35 1T
Video Card ASUS GTX 980 STRIX (1178/1279 Boost)
Hard Drive Crucial MX300 1TB
Case Open Test Bed
Operating System Windows 10 Pro 64-bit

Readers of our motherboard review section will have noted the trend in modern motherboards to implement a form of MultiCore Enhancement / Acceleration / Turbo (read our report here) on their motherboards. This does several things, including better benchmark results at stock settings (not entirely needed if overclocking is an end-user goal) at the expense of heat and temperature. It also gives, in essence, an automatic overclock which may be against what the user wants. Our testing methodology is ‘out-of-the-box’, with the latest public BIOS installed and XMP enabled, and thus subject to the whims of this feature. It is ultimately up to the motherboard manufacturer to take this risk – and manufacturers taking risks in the setup is something they do on every product (think C-state settings, USB priority, DPC Latency / monitoring priority, overriding memory sub-timings at JEDEC). Processor speed change is part of that risk, and ultimately if no overclocking is planned, some motherboards will affect how fast that shiny new processor goes and can be an important factor in the system build.

New Test Suite: Spectre and Meltdown Hardened

Since the start of our Z390 reviews, we are using an updated OS, updated drivers, and updated software. This is in line with our CPU testing updates, which includes Spectre and Meltdown patches. 

Many thanks due to...

Thank you to ASUS for providing us with GTX 980 Strix GPUs. At the time of release, the STRIX brand from ASUS was aimed at silent running, or to use the marketing term: '0dB Silent Gaming'. This enables the card to disable the fans when the GPU is dealing with low loads well within temperature specifications. These cards equip the GTX 980 silicon with ASUS' Direct CU II cooler and 10-phase digital VRMs, aimed at high-efficiency conversion. Along with the card, ASUS bundles GPU Tweak software for overclocking and streaming assistance.

The GTX 980 uses NVIDIA's GM204 silicon die, built upon their Maxwell architecture. This die is 5.2 billion transistors for a die size of 298 mm2, built on TMSC's 28nm process. A GTX 980 uses the full GM204 core, with 2048 CUDA Cores and 64 ROPs with a 256-bit memory bus to GDDR5. The official power rating for the GTX 980 is 165W.

The ASUS GTX 980 Strix 4GB (or the full name of STRIX-GTX980-DC2OC-4GD5) runs a reasonable overclock over a reference GTX 980 card, with frequencies in the range of 1178-1279 MHz. The memory runs at stock, in this case 7010 MHz. Video outputs include three DisplayPort connectors, one HDMI 2.0 connector and a DVI-I.

Further Reading: AnandTech's NVIDIA GTX 980 Review

Thank you to Crucial for providing us with MX200/MX300 SSDs. Crucial stepped up to the plate as our benchmark list grows larger with newer benchmarks and titles, and the 1TB units are strong performers. The MX200s are based on Marvell's 88SS9189 controller and using Micron's 16nm 128Gbit MLC flash, these are 7mm high, 2.5-inch drives rated for 100K random read IOPs and 555/500 MB/s sequential read and write speeds. The 1TB models we are using here support TCG Opal 2.0 and IEEE-1667 (eDrive) encryption and have a 320TB rated endurance with a three-year warranty.

Further Reading: AnandTech's Crucial MX200 (250 GB, 500 GB & 1TB) Review

Thank you to Corsair for providing us with Vengeance LPX DDR4 Memory

Corsair kindly sent a set of their Vengeance LPX low profile, high-performance memory. The heatsink is made of pure aluminum to help remove heat from the sticks and has an eight-layer PCB. The heatsink is a low profile design to help fit in spaces where there may not be room for a tall heat spreader; think a SFF case or using a large heatsink.

BIOS And Software System Performance


View All Comments

  • drajitshnew - Tuesday, March 12, 2019 - link

    Thanks for this review, this mobo has some very good design choices. Is there some way the post latency can be improved in THIS board. Reply
  • EliteRetard - Tuesday, March 12, 2019 - link

    On a similar note, why is it listed as "Non-UEFI POST Time"? Are you actually disabling UEFI and going with a legacy BIOS for post time? Why, and how does that affect post time? I imagine anybody using this board will want to use UEFI.

    I am glad that POST time is being measured though, it's an important metric for me and many people I build computers for. Some people might think it unimportant, but when POST vary so drastically the differences are very tangible. Most of the people I build computers for also directly correlate bootup times to the performance of the machine (no matter how many times I try to explain it). I know I still would never accept a MOBO with a 30sec POST time.
  • GreenReaper - Tuesday, March 12, 2019 - link

    They may mean "non-Graphical", but still using UEFI under the hood. It's unlikely to have display acceleration, so it takes extra CPU time to draw fancy pictures (as I found when using graphical console modes on my Linux microserver - 8-bit and 16-bit were proportionately faster than 24-bit). Reply
  • gavbon - Wednesday, March 13, 2019 - link

    You can't disable UEFI as UEFI and BIOS are both types of firmware and in themselves, they aren't the same. With the UEFI firmware and CSM, it can emulate or pretend to POST like a non-UEFI BIOS. This is a more consistent way of doing things to show performance across a range of boards etc Reply
  • close - Thursday, March 14, 2019 - link

    But it would help to tell us what the boot time is with "optimized defaults" so to speak. I mean it's great if you can "show performance across a range of boards" but why mention only how long it take is non-UEFI mode for comparison? Why not also in UEFI mode? Is that comparison not useful? Or is the board always in non-UEFI mode? Reply
  • kobblestown - Wednesday, March 13, 2019 - link

    Yes, this MB has some good design choices. For the price. I would have preferred to have either a 10G Ethernet adapter or a PCIe2.0x4 slot, e.g. where the heatsinked M.2 slot is (and the battery should be moved somewhere else. In my opinion 10G is taking off (I already have a direct 10G link between my X399 and my server) and will soon be within reach for most consumers. Having to occupy a x16 slot for a 10G adapter sends shivers down my spine. Plus, you could also wish to use a 4x4 bifurcation adapter board to install more nvme SSDs (3 is sometimes not enough) and then you'll be left with a single slot for a GPU.

    As for the POST times, I hope they can get them down to the other X399 boards. I see no reason why it should be twice longer. I have the Asrock X399 Professional Gaming and POST is already excruciatingly slow. Probably the panoply of PCIe devices is to blame (lspci shows more than 60 devices apart from the user-installed ones!)
  • Kevin G - Tuesday, March 12, 2019 - link

    I think this needs to be edited a bit for clarity on page 1:

    "The audio PCB is separate from the rest of the PCB"

    There is no separate audio PCB from the pictures I see as implied by that statement. I think the intent was to read 'the audio circuitry is separate from the rest of the PCB'.
  • Kevin G - Tuesday, March 12, 2019 - link

    Two more on page 4:

    "For the start of our Z390 reviews" I think should read "Since the start of our Z390 reviews"


    "Many due to..." I thank you missed a word there. ;)
  • Ryan Smith - Wednesday, March 13, 2019 - link

    Thanks! Reply
  • lmcd - Tuesday, March 12, 2019 - link

    *separate PCB layer

    which is in fact true (or at least their marketing claims as much)

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