ASUS ROG STRIX X299-E Gaming Review


  • Author: MAC
  • Date: September 27, 2017

A Closer Look at the X299-E Gaming


Much like the Maximus IX Hero that we reviewed earlier this year, the STRIX X299-E features a sleek black and grey aesthetic. While the black slots and black PCB are fairly uniform, there’s just about every possible shade of grey imaginable found on the metallic heatsinks, the plastic shrouds, the various connectors, and there’s even silkscreened grey stripes onto the PCB. Overall though, it combines into another relatively understated but good looking motherboard from ASUS.

This model is based on the conventional full-size ATX form factor – 30.5 cm x 24.4 cm / 12.0-in x 9.6-in – so there are no compatibility issues to worry about with any properly designed case. The overall layout is very well-thought-out and there are no critical shortcomings that we can point out. All the buttons and switches, numerous connectors and ports are easily accessible and free from possible obstruction. We appreciate the fact that there is a huge amount of space between two primary PCI-E x16 slots, so there won’t be any issues fitting thick dual or even triple-slot graphics cards on this motherboard. We also like the placement of the M.2 slots – one under the chipset heatsink and one vertical slot next to the memory slots – since many motherboards seem to place at least one slot directly under the primary graphics card, which is a problem because very high performance M.2 solid state drives have been known to throttle themselves when running too hot.


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Looking at the CPU socket area, we see a very wide open area. People using conventional air or liquid cooling won’t have any installation issues, and those using more exotic methods can further increase the work space by just removing that plastic ROG logo below the CPU socket. When it comes to the MOSFET cooler, that heatsink is really just a block of aluminium, with minimal surface area due to a general lack of fins and no heatpipe to help wick away the heat. As we will explain below, it works adequately but a more robust solution would b preferred to help improve VRM temperatures.

After we removed the rear I/O shroud, and disconnected the cable that powers the RGB LED PCB, we were able to get a good look at this motherboard’s VRM area. It features a 7+1 phase CPU power design that utilizes a Infineon IR35201 digital PWM controller that has been rebranded by ASUS as ASP1405I, and a mix of seven excellent Infineon PowIRstage IR3555M 60A MOSFETs for the CPU cores and one smaller but also excellent Texas Instruments CSD97374Q4M NexFET, likely for VCCSA.

Since Skylake-X processors – particularly the 10+ core models – require an unbelievable amount of power when heavily overclocked, ASUS have included one 8-pin CPU power connector and a supplementary 4-pin CPU power connector. This is a welcome addition since very highly overclocked processors can draw a ton of current through the 8-pin CPU power connector, enough to trip up certain power supplies with wonky over-current protection (OCP). Even if that doesn’t happen, when we pulled over 450W from the 8-pin connector (otherwise known as EPS12V) it did start warming up quite a bit, reaching a peak temperature of about 66°C. That’s not problematic, but there’s no downside to sharing the load across two connectors if you can.

While we are on the topic of overclocking and temperatures and VRM, there really is no critical issue here. Yes, stress testing an overclocked and overvolted Core i9-7900X with the latest builds of Prime 95 can push the VRM on this (and any) X299 motherboard to start throttling due to high temperatures (105°C/221°F). However, no other program or even combination of programs comes even close to recreating Prime 95’s FFTs load level. For example, we set our manual overclock and used the system for an entire week – essentially fully loaded 24/7 – with a combination of benchmarking, gaming, video encoding, and mining, and the peak MOSFET temperature that was recorded was 82°C, which is perfectly acceptable to us. If you’re installing a Kaby Lake-X processor, none of this applies. You can run Prime 95 as long as you want since those chips don’t support AVX-512 and they just aren’t particularly power hungry.

Speaking of cooling, next to the CPU power connectors are the two 4-pin CPU fan headers, which like all five system fan headers are fully controllable via both DC and PWM fan control modes from within the UEFI and the Fan Xpert 4 utility. While the two CPU fan headers can only supply up to 1A/12W, ASUS have actually added a dedicated AIO fan header and a separate water pump header, both of which can provide up to 3A. There’s also two case fan headers, and even an M.2 fan header that can be used as a third case fan, for a grand total of seven system fans. If that wasn’t enough, ASUS have also added their EXT_FAN header that allows you to install their optional fan extension card (sold separately).


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Since Skylake-X chips feature a quad-channel memory interface, this motherboard has eight DDR4 memory slots, with each bank of four slots being fed by a 2-phase power design. When a dual-channel Kaby Lake-X processor is used only the right bank of memory slots are supported. ASUS have validated the X299-E for overclocked memory frequencies up to DDR4-4133 for both chip types. Skylake-X processors can support up to 128GB of system memory, while the Kaby Lake-X parts top out at 64GB. ASUS have as usual implemented DRAM overcurrent protection (OCP) and short circuit damage prevention, so you will be able to push your DDR4 modules as hard as you want without worrying that the power delivery will let you down.

Regrettably, there is no MemOk! button on this model. We generally appreciate that feature since it initiates a memory compatibility tuning process if there are memory issues preventing a system from booting up. However, there are diagnostic LEDs in the top-right corner, and they can be used to diagnose CPU/RAM/GPU/Boot device issues during boot up.

Like on all ASUS motherboards, this model features the handy Q-DIMM memory slots, which prevent any clearance issues that can arise between conventional memory clips and the back of any nearby expansion card. As always, the 24-pin ATX power connector is in its usual spot.


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Next to the 24-pin ATX power connector is a vertical M.2 slot, which might look weird but is a great alternative to placing an M.2 slot under the primary graphics card. Placing an M.2 slot directly under a graphics card is a problem because very high performance NVMe solid state drives have been known to throttle themselves when running too hot. This is a full-speed PCI-E 3.0 x4 slot, with a theoretical maximum bandwidth of 32Gb/s, and support for SATA, PCI-E, and PCI-E NVMe M.2 solid state drives. It also supports Intel’s Optane Memory SSDs and RAID 0/1 in coordination with the other M.2 slot.

To the left of the M.2 slot is a USB 3.1 Type-C front panel header. Those with newer cases that support this latest USB standard will finally be able to direct all of that speed to the front USB 3.1 ports. This capability is courtesy of a brand new ASMedia ASM3142 USB 3.1 Gen2 host controller that supports transfer rates of up to 16Gb/s. This header shares bandwidth with the PCI-E x1 slot, so both cannot be used at the same time.

To the left of the USB 3.1 Type-C header is an angled USB 3.0 header that is powered by the X299 chipset, it can provide two USB 3.0 ports to the front of your case.


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This little plastic doodad – that is located in the old school northbridge position – is really more of an aesthetic touch, since there is not much under it aside from some small electrical components. While it’s hard to properly represent in pictures, the ROG logo is laser etched into a plastic crystal-like material, and there’s a holographic effect due to a mirror that is placed under the clear plastic. There are also RGB LEDs integrated into this contraption, and it looks pretty darn cool when all lit up.


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This motherboard features eight SATA 6Gb/s ports, all of which are supplied by the X299 PCH and as a result support RAID 0/1/5/10 plus Intel Rapid Storage Technology 15. Keep in mind that if you use the second PCI-E x4 slot, that will disable four of the eight SATA ports. Likewise, if you install a SATA M.2 SSD in the M.2 slot under the PCH heatsink, you will lose access to one SATA port.

We are quite pleased that ASUS chose not to include a U.2 port, since that interface can be added by the user via a ASUS Hyper Kit M.2 to Mini SAS HD adapter. Instead, they have focused their efforts on designing a cool chipset heatsink that serves double duty as a cooler for a M.2 solid state drive. While similar concepts have had mixed results, this piece of aluminium is large enough that it can absorb quite a bit of the SSD’s thermal emissions before getting heat soaked. We actually noticed a general 4-5°C improvement in temperatures with this heatsink on our Samsung 950 PRO. More critically however, it also serves to protect the SSD from the heat that would radiate from any graphics card installed in the second PCI-E x16 slot.

Much like the vertical M.2 slot, this one features a full-speed PCI-E 3.0 x4 link, with a theoretical maximum bandwidth of 32Gb/s, and support for SATA, PCI-E, and PCI-E NVMe M.2 solid state drives. It also supports Intel’s Optane Memory SSDs and RAID 0/1. It can even handle extra-longer 22110 M.2 drives, which are 110mm long compared to the 80mm length of conventional 2280 drives.

If you paid attention during Computex 2017, you may have noticed that Intel and the various motherboard manufacturers were really touting the Virtual RAID on CPU (VROC) feature. This new concept allows multiple M.2 PCI-E drives to run off of the CPU’s PCI-E lanes and form a bootable RAID array. RAID 0 is the default mode, and if you want other RAID modes you need to purchase a physical VROC Key. Although there is a VROC Key header on this model, neither the hardware VROC Key or the multi-M.2 PCI-E adapters are being sold at this time. Also, the fact that VROC requires a Skylake-X processor and only supports Intel SSDs is another issue, one that makes this entire feature rather pointless given the sorry state of Intel’s current M.2 NVMe offerings (ie: the 600p).

Directly to below the M.2 slot is a 3D Mount standoff, so those with 3D printers can make some type of new or different M.2 cover/shield/shroud. We aren’t exactly sure who would want to do this, but if interested you can read up on what ASUS has to say about it.

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