ASUS PRIME X399-A Motherboard Review

Author: MAC
Date: December 5, 2017
Product Name: PRIME X399-A
Part Number: PRIME X399-A
Warranty: 3 Years
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Earlier this month we reviewed our first ThreadRipper-supporting X399 motherboard, and as luck would have it was one of the most feature packed models on the market: the ASRock Fatal1ty X399 Professional Gaming. The downside of features is that they always carry a price, and in the case of this ASRock motherboard that price was an eye-watering $660 up here in Canada. When you combine that with the $700 or $1050 or $1250 for a ThreadRipper processor, the total starts to add up quickly. With this in mind, we went on the lookout for a budget-friendly X399 motherboard, and failing at that task, we settled the next best thing.

At $350 USD / $450 CAD, the ASUS PRIME X399-A is one of the least expensive motherboards with an AMD TR4 socket. We will shy away from using the word affordable though, since $450 is still a heck of a lot of money for any non-sentient piece of computer hardware. Clearly, AMD is selling the X399 chipset for a very healthy profit, but we digress...

What do you get for you money? Well for starters, this model has an 11-phase CPU VRM made from the best available components, four steel-reinforced PCI-E 3.0 x16 slots that support both 3-way CrossFire and 3-way SLI, one PCI-E 2.0 x4 slot, and one PCI-E 2.0 x1 slot. Those who need a ton of I/O connectivity might be disappointed since this model only has two full-size M.2 x4 slots, six SATA 6Gb/s ports, and one U.2 NVME port. Both the number of M.2 slots and SATA ports are below average for an X399 motherboard. However, the USB connectivity is off-the-charts. There are two high speed USB 3.1 Gen2 ports on the rear I/O panel, one Type-A and one Type-C, as well an internal USB 3.1 Gen2 Type-C header that can provide up two ports to the front of the case. On the rear I/O there are an impressive eight USB 3.0 ports, which are further bolstered by two internal USB 3.0 headers. When you combine all of that with the two USB 2.0 headers there are a grand total of twenty USB ports at your disposal.

When it comes to networking the PRIME X399-A isn't going to impress anyone, since despite its lofty pricetag it only has a single gigabit LAN port. No redundant ports, no onboard Wi-Fi, or certainly no ten gigabit connectivity. This seems rather stingy to us, but since the other X399 motherboards in this price range also only have one LAN port clearly everyone is needing to penny pinching in order to reach this price point.

Much to our surprise this cost cutting extended to the audio section as well. While the Crystal Sound 3 onboard audio solution is based on the familiar Realtek ALC1220 ten-channel codec and linked to an array of Nichicon audio-grade capacitors, there is no separate Texas Instruments op-amp for the front panel headphone output. Instead, ASUS are utilizing the amplifier that is built into the codec itself. While that is a perfectly workable solution, it is a bizarre move given that dedicated op-amps have become standard equipment on most motherboards above $150. It will be interesting to see what the audio results look like.

Thankfully there are little extras, we appreciate the Q-Code debug LED, the BIOS Flashback button that allows you to flash the UEFI without powering on the system, and the onboard thermal sensor header. The onboard power button is hugely handy for those with test benches, but the lack of a reset or even clear CMOS button is disappointing since there is ample room for them next to the power button. There are seven total fan headers, all of which are four-pin PWM/DC capable and are fully controllable from within the UEFI and the Fan Xpert 4 utility. Two of those seven fan headers are dedicated towards AIO and water pumps.

While this introduction is perhaps not the most auspicious beginning to a motherboard review, at least some of our concerns and criticisms can be overshadowed if everything works as well as it should, or even better surpasses our expectations. So if you're interested in AMD's new HEDT platform, and need to find the most economical way to own it, this motherboard might just be what you're looking for.


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