Asus ROG Strix X299-E Gaming ATX Motherboard Review: 44-Lane CPU Ready

The idea of a $300 board being mainstream might sound ludicrous, but entry-level X299 boards cost around $200, and Intel’s high-end desktop series is designed for big spenders. Mid-level might be a better term for this price, and the Asus ROG Strix X299-E Gaming (which sells for at or just under $300 when we wrote this) gets there with a combination of dual USB 3.1 Gen2 controllers, a 867Gb/s Wi-Fi module, enhanced overclocking and competitive RGB lighting features.



LGA 2066


Intel X299

Form Factor


Voltage Regulator

Eight Phases

Video Ports

USB Ports

10Gbps: (1) Type-C, (3) Type A
5Gb/s: (4) Type A; (2) USB 2.0

Network Jacks

Gigabit Ethernet, (2) Wi-Fi Antenna

Audio Jacks

(5) Analog, (1) Digital Out

Legacy Ports/Jacks

Other Ports/Jack

USB BIOS Flashback I/O-Panel Button

PCIe x16

(3) v3.0 (@44: x16/x16/x8)
@28: (x16/x8/x1)
@16: (x16/x0/x1, x8/x8/x1)

PCIe x8

PCIe x4

(2) x4*/x1 (*Consumes SATA ports 5-8)

PCIe x1

(1) v3.0 (Consumes front-panel USB 3.1 Gen2)


3x / 3x

DIMM slots

(8) DDR4

M.2 slots

(1) PCIe 3.0 x4 / SATA*, (1) PCIe 3.0 x4,
(1) Key-E (Filled); (*Consumes SATA port 1)

U.2 Ports

SATA Ports

(8) 6Gb/s (Ports 1,  5-8 shared w/M.2, PCIe x4)

USB Headers

(1) 10Gb/s Type-C*, (2) v3.0, (1) v2.0
(*Shared w/PCIe x1)

Fan Headers

(7) 4-Pin, (1) Extender Card Header

Legacy Interfaces

Serial COM Port

Other Interfaces

FP-Audio, (2) RGB-LED, ADD-RGB, VROC_Key, Thermistor

Diagnostics Panel


Internal Button/Switch


SATA Controllers

Integrated (0/1/5/10)

Ethernet Controllers


Wi-Fi / Bluetooth

RTL8822BE 802.11ac 2x2 (867Mb/s) / BT 4.2 Combo

USB Controllers

(2) ASM3142 PCIe 3.0 x2, ASM1074 Hub

HD Audio Codec


DDL/DTS Connect


3 Years

Unlike many mid-level boards though, the ROG Strix X299-E Gaming requires a 44-lane CPU to effectively use its third x16-length PCIe slot. Although it's a solid-enough board to encourage a few buyers, that limitation is a big hindrance to our overall recommendations.

The Strix X299-E Gaming has two antenna connections for Realtek’s 2T2R 802.11ac module and two ports (Type-C and Type A) for ASMedia’s PCIe 3.0 x2 USB 3.1 Gen2 controller on its I/O panel. There's also a USB BIOS Flashback button, which uses a special ASIC (application-specific integrated circuit) to enable flashing firmware without the need for a compatible CPU or DRAM. Other I/O panel features include four USB 3.0 (aka USB 3.1 Gen1), two USB 2.0, digital optical audio output and five analog audio jacks.

Zooming out shows the extremes Asus went to for the board to represent the ROG brand aesthetically, from the lighted sliver on the I/O connector hood, to the machined aluminum voltage regulator sink, the M.2 heat spreader integrated into the PCH sink cover and ROG lightbox badge at the motherboard's center. Two open-ended PCIe x4 slots add to the three x16 slots to boost enablement of serious connectivity.

Given the board’s support for everything from 44-lane to 16-lane processors, you’d expect to see the double-row of eight two-lane PCIe switches under its top slot. The surprise comes in the other three switches to the side of that group, as the lower PCIe x4 slot steals all four HSIO resources (Intel’s flexible SATA/USB3/SATA pathways) from SATA ports 5-8. And if you were thinking of using the PCIe x1 slot instead, note that doing so will switch off the front-panel USB 3.1 Gen2 connector. Given that you’ll probably have a graphics card covering the x1 slot, you might be un-enthused to learn that the upper PCIe x4 slot has only one pathway.

Compromises on the smaller slots are understandable to those familiar with Intel’s chipset limitations, particularly given the market’s focus on x16 slots. While a 44-lane CPU can shoot an x16/x16/x8 configuration and x16 processors spit an x8/x8/x1 configuration by borrowing a lane from the chipset, options for 28-lane processors teeter on the edge of infuriating: Asus says the top slot is locked at x16 mode with those processors, the middle slot gets eight CPU pathways, and the lower slot still gets only a single pathway from the chipset. Asus gives no excuses or explanations for why it couldn’t do a three-by-eight configuration for three-way SLI on 28-lane processors, nor does it say why the CPU’s other four lanes are ignored.

Layout is fairly good in spite of configuration limitations that are peculiar to the installation of a 28-lane CPU. All of the ports in front of the slots (eight SATA and one dual-port USB 3.0 header) point forward to allow installation of extra long cards. There are two case fan headers near the back of the board for easier reach to the back panel, and two CPU fan headers are just above the rear banks of memory to ease installation.

A perpendicular M.2 storage slot is found south of the 24-pin power connector, and there's a front-panel USB 3.1 interface just south of that. The USB interface gets a controller to itself, though that controller shares its pathway with--and is disabled by--the PCIe x1 slot. Similarly, the M.2 slot features four PCIe lanes for NVMe, but users of SATA M.2 drives are forced to sacrifice SATA port to when using that connection. A bracket within the installation kit allows builders to lock down their M.2 module.

The bottom of the ROG Strix X299-E Gaming has a front-panel audio header, one (of two) RGB LED cable connectors, an old-fashioned 9-pin Serial Port breakout plate header, a two-digit diagnostics code display, a power button, a special header for Asus’ aftermarket Fan Extension card, a second USB 3.0 front-panel header that can’t be used when a graphics card is installed in the bottom slot, two (of seven) four-pin fan headers, an addressable LED strip header and a standard Intel front-panel switch/LED group (9-pins) with adjacent connections for a beep-code speaker and legacy spaced (3-pin) power LED. The Intel VROC (virtual RAID on CPU) module header, which adds a RAID firmware module for NVMe drives connected to the CPU-based PCIe controller via the board’s x16 slots, is above the lower-front-corner connectors.

The ROG Strix X299-E Gaming includes a driver and application disc in the box, along with a manual, I/O shield, a riser bracket for the perpendicular M.2 slot, a two-channel Wi-Fi antenna, a high-bandwidth SLI Bridge for two cards, a pack of cable ties, four SATA cables (two with a right angle end), an Asus Q-connector bundling block for front panel power/LED leads, a thermistor lead, an RGB extension cable, an addressable LED strip extension cable, a sheet of adhesive cable labels, an Asus special offer card for, an ROG sticker sheet and a “Do Not Enter” door handle card.

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