Today we had an opportunity to look at another motherboard in the MSI lineup. Instead of coming from the Enthusiast, Performance, or Arsenal line of products, the MSI X299 SLI Plus hails from their Professional line of motherboards. The SLI Plus is often cited as a low-cost, 'meets almost everyone's needs' type of board, and previous iterations have worked well in the past. We put it on the test bed for a thorough inspection.

The MSI X299 SLI Plus

The SLI Plus range of MSI motherboards is a brand that aims for a low-cost price point, but uses the overclocking chipset to aim for the entry level of performance-per-dollar while still retaining all the key chipset features as well as a number of aesthetics. These boards are geared up for almost anyone: gamers, users, professionals, all of whom do not want extra 'fluff' and can provide their own controllers. These boards still use good quality components, and they are not completely stripped down, but it is usually clear that the SLI Plus often has a lower profit margin than some other boards. We reviewed the Z270 SLI Plus at the beginning of this year, when it beat out a similarly priced competitor, and the Z170 SLI Plus in Q2 2016, where it achieved one of our rare 'AnandTech Recommended' awards. The X299 SLI Plus has a legacy to live up to.

Overall, the CPU performance on the X299 SLI Plus was above average, managing to beat out comparable boards in some tests due to the use of Multi-Core Enhancement. Some tests were more affected by MCE than others which was a little strange, especially as other MSI boards with MCE performed better in some tests as well. We are not entirely sure why this happened as the testing used the exact same settings and drivers. Even turbo/clock speeds were the same in both tests, so it might be related to how the board ramps up and down the frequency on the local environment at the time. 

On non-CPU performance, startup times were in the middle of the pack, while power use was slightly higher than the previous X299 boards tested. Overclocking results were the same as our other high-end motherboard tests, with our i9-7900X hitting 4.5 GHz at our temperature limit. The voltage needed to reach the clocks was slightly less, though not enough to push past our current temperature limited clock speeds. The small variance could also be due to software since the board does not have voltage read points to confirm with a digital multi-meter.

For features, the storage connectivity of the MSI X299 SLI Plus has eight SATA ports from the chipset, as well as two M.2 slots and a U.2 port, which are also funneled through the chipset. Lane sharing and port availability will need to be considered when attaching some of these peripherals, which is an issue that should have been solved with the new chipsets. The SLI Plus brings two USB 3.1 (10 Gbps) ports on the rear panel, in Type-A and Type-C connectivity, and a front panel 10 Gbps port, all of which are handled by two ASMedia 3142 controllers. Five USB 3.1 (5 Gbps ports) and eight USB 2.0 ports also go through the chipset, while an additional three USB 3.1 (5 Gbps) ports are from an ASMedia ASM1074 hub. Networking comes from dual Intel I219-V Gigabit ports. 

For a Pro Series or workstation type board, there are enough options for almost any use. On the professional side of things, the addition of the U.2 slot gives users some additional flexibility (it would be more relevant if more vendors would release more drives). If multi-GPU gaming is a consideration, the SLI Plus covers that option supporting both NVIDIA 2-Way SLI and 3-Way AMD Crossfire configurations. Other functionality, such as 10 GbE, can be added via a card if needed (especially if our readers picked up one of the Aquantia 5/10 GbE cards on offer recently). Regarding overclocking, the board reached the CPUs 4.5 GHz limit with our cooling without signs of throttling and performed admirably in our tests, but used a little more power than other boards in doing so. 

The MSI X299 SLI Plus is the flagship offering in MSI's 'Pro Series' X299 motherboard lineup. With it are two other boards, the X299 Raider and the MicroATX X299M-A Pro. The Raider offers a couple fewer features, for example, no integrated RGB LEDs, one less x1 PCIe slot, and will also cost less. The MicroATX board drops a full-length PCIe slot (down to 3), does not have an x1 sized PCIe slot, but does have RGB LEDs on the shroud. "Pro Series" nomenclature aside, the X299 SLI Plus is a feature rich board for a base X299 implementation. Features such as reinforced PCIe slots, a debug LED, a front panel USB 3.1 (10 Gbps) header, eight SATA ports versus six, a dual BIOS, dual NICs, as well as the top Realtek ALC1220 codec, all find their way to the SLI Plus. The U.2 slot, not found on many boards in the MSI lineup, gives users more flexibility with storage options than the standard SATA and M.2. 

The X299 SLI Plus is currently priced at $231.89 (from $259.99) at This price point puts it in the ballpark of some Arsenal boards like the Tomahawk ($270) and Tomahawk Arctic ($280) which we also recently reviewed. The X299 Raider is priced at ($220). Outside of MSI, price wise, the SLI Plus competes with boards such as the ASUS TUF X299 Mark 2 ($260 w/Free Assasin's Creed Game), the Gigabyte X299 AORUS Gaming 3 ($250), as well as the ASRock X299 Gaming K6 ($250). 


MSI's X299 Strategy

MSI brings a current total of 11 X299 boards to choose from: the MSI X299 XPower Gaming AC holds the flagship title and makes its home in the Enthusiast Gaming segment along with the X299 Gaming M7 ACK. There are a total of three boards in the Performance Gaming hierarchy in the X299 Gaming Pro Carbon AC, Gaming Pro Carbon, and X299M Gaming Pro Carbon AC (mATX). The Arsenal line carries the three Tomahawk boards, the X299 Tomahawk, the X299 Tomahawk Arctic and the X299 Tomahawk AC, while the Pro lineup for professionals has three motherboards; X299 SLI Plus, X299 Raider, and X299M-A Pro.

MSI's X299 Motherboard Lineup (11/29)
Amazon Newegg
X299 XPower Gaming AC   $450 $450
X299 Gaming M7 ACK   $366 $380
X299 Gaming Pro Carbon AC Review 9/21 $273^ $330
X299 Gaming Pro Carbon   $320 $320
X299M Gaming Pro Carbon AC   Coming December*
X299 Tomahawk AC   $273 $290
X299 Tomahawk Arctic Review 11/20 $280 $280
X299 Tomahawk   $256 $270
X299 SLI PLUS [this review] $232 $220
X299 Raider   $215 $220
X299M-A Pro   - $237^

*The X299M Gaming Pro Carbon (and the X299M-A Pro), according to our MSI USA contacts, is coming in December. It currently has not hit the US market for some unknown reasons, but we were able to confirm it is coming, and rather soon.

^Third-Party Price

Information on Intel's X299 and our other Reviews

 With Intel's release of the Basin Falls platform, encompassing the new X299 chipset and LGA2066 socket, a new generation of CPUs called Skylake-X and Kaby Lake-X were also released. The Skylake-X CPUs range from the 7800X, a hex-core part, all the way up to an 18-core 7980XE multitasking behemoth. Between the bookend CPUs are five others increasing in core count, as in the table below. The latter HCC models are set to be launched over 2H of 2017. 

Skylake-X Processors
  7800X 7820X 7900X   7920X 7940X 7960X 7980XE
Silicon LCC   HCC
Cores / Threads 6/12 8/16 10/20   12/24 14/28 16/32 18/36
Base Clock / GHz 3.5 3.6 3.3   2.9 3.1 2.8 2.6
Turbo Clock / GHz 4.0 4.3 4.3   4.3 4.3 4.3 4.2
Turbo Max Clock N/A 4.5 4.5   4.4 4.4 4.4 4.4
L3 1.375 MB/core   1.375 MB/core
PCIe Lanes 28 44   44
Memory Channels 4   4
Memory Freq DDR4 2400 2666   2666
TDP 140W   140W 165W
Price $389 $599 $999   $1199 $1399 $1699 $1999

Board partners have launched dozens of motherboards on this platform already, several of which we will have an opportunity to look over in the coming weeks and months. This specific review will cover the MSI X299 SLI Plus. 

Other AnandTech Reviews for Intel’s Basin Falls CPUs and X299

As we are in the process of testing more and more motherboards, some of the benchmark results in this review will contain numbers from motherboards we have not published a full review yet. Here's our current list of motherboards on the go, as well as some of our CPU reviews:

  • The Intel Skylake-X Review: Core i9-7980XE and Core i9-7960X Tested
  • The Intel Skylake-X Review: Core i9-7900X, i7-7820X and i7-7800X Tested
  • The Intel Kaby Lake-X Review: Core i7-7740X and i5-7640X Tested
  • Intel Announces Basin Falls: The New High-End Desktop Platform and X299 Chipset
  • ($390) The ASRock X299 Professional Gaming i9 Review: [link
  • ($360) The MSI X299 Gaming Pro Carbon Review [link
  • ($300) The MSI X299 Tomahawk Arctic Review [link]
  • ($289) The ASRock X299 Taichi Review [link]
  • ($260) The MSI X299 SLI Plus Review (this review)
  • ($510) The ASRock X299E-ITX/ac Review (writing up) 
  • ($500) The GIGABYTE X299 Gaming 9 Review (planned) 
  • ($400) The GIGABYTE X299 Gaming 7 Review (planned)
  • ($350) The ASUS Strix X299-E Gaming Review (being tested) 
  • ($337) The ASUS X299 TUF Mark 1 Review (being tested) 
  • ($330) The EVGA X299 FTW-K (arrived)
  • ($290) The EVGA X299 Micro (arrived)
  • ($?) The EVGA X299 Dark (planned)

To read specifically about the X299 chip/platform and the specifications therein, our deep dive into what it is can be found at this link.

X299 Motherboard Review Notice

If you’ve been following the minutiae of the saga of X299 motherboards, you might have heard some issues regarding power delivery, overclocking, and the ability to cool these processors down given the power consumption. In a nutshell, it comes down to this:

  • Skylake-X consumes a lot of power at peak (150W+),
  • The thermal interface inside the CPU doesn’t do much requiring a powerful CPU cooler,
  • Some motherboard vendors apply Multi-Core Turbo which raises the power consumption and voltage, exacerbating the issue
  • The VRMs have to deal with more power, and due to losses, raise in temperature
  • Some motherboards do not have sufficient VRM cooling without an active cooler
  • This causes the CPU to declock or hit thermal power states as to not degrade components
  • This causes a performance drop, and overclocked systems are affected even more than usual

There has been some excellent work done by Igor Wallossek over at Tom’s Hardware, with thermal probes, thermal cameras, and performance analysis. The bottom line is that motherboard vendors need to be careful when it comes to default settings (if MCT is enabled by default) and provide sufficient VRM cooling in all scenarios – either larger and heavier heatsinks or moving back to active cooling.

This means there are going to be some X299 boards that perform normally, and some that underperform based on BIOS versions or design decisions. We are in the process of quantifying exactly how to represent this outside of basic benchmarking, so stay tuned. In the meantime, take a look at the next motherboard for review. 

Visual Inspection
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  • Vatharian - Wednesday, November 29, 2017 - link

    Why, why manufacturers won't let the U.2 die? We are already past SATA Express, and now this. I get it, it's one of the most popular connectors to connect SAS backplanes, and most of HBAs and RAID controllers do use it, but please, let it die in desktop space. If anything SFF8087 should remain, as SFF-8639 (U.2) is much flimsier and easier to break.

    Also, we already have far superior standard just behind the corner, in the form of OCuLink.
  • peterfares - Wednesday, November 29, 2017 - link

    Why not have it there though? X299 is a prosumer platform, they may want to use U.2 drives.
  • Lolimaster - Wednesday, November 29, 2017 - link

    x399 laughs at X299 being called "prosumer" 44pci-e lanes vs 64 pci-e lanes, bootable nvme raid support.
  • BillyONeal - Wednesday, November 29, 2017 - link

    I'm a "prosumer" who built both X299 and X399 boxes and couldn't care less about those things. Compiler want MOAR CORRRREEEESSSSSS
  • drajitshnew - Friday, December 1, 2017 - link

    Why call it a prosumer product when it doesn't have ANY m2/u2 connected to the processor?
  • andychow - Wednesday, November 29, 2017 - link

    Doubtful it will disappear. With Optane coming out with only a U.2 connector on the SSD format, it rather insured that U.2 will grow in demand.
  • BillyONeal - Wednesday, November 29, 2017 - link

    The 750 was also like that but didn't spur demand for U.2. The add-in cards are just fine.
  • Dr. Swag - Wednesday, November 29, 2017 - link

    Could you guys do some better vrm testing? X299 vrms have been a hot topic (pun intended) due to Skylake X drawing a lot of power when OCed and because of the addition of up to 18 cores. Some vrms get quite toasty under load so if you guys had good vrm temp measurements and perhaps even measurements on voltage ripple and stuff coming out of the vrm that would be awesome.
  • - Wednesday, November 29, 2017 - link

    And let's not forget measurement of VRM power efficiency to compare the quality of VRMs across motherboards!
  • Lolimaster - Wednesday, November 29, 2017 - link

    Just but Threadripper and forget about those problems.

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