Introduction, Design Features
The MSI X299 SLI Plus is one of the first wave of motherboards to support Intel’s Core X-Series CPUs. The motherboard straddles the business and consumer markets, capable of being the foundation of a hip professional workstation or a home-use gaming ultra-PC. And although you can find plenty of other X299-based motherboards that are more overtly designed for gaming (even ones by MSI itself), the MSI X299 SLI Plus wouldn’t be at all out of place in a gaming build, either.
Part of MSI’s Pro Series of motherboards, the X299 SLI Plus has fewer lighting options and gaming-related features than the company’s X299 Tomahawk and X299 Gaming boards. But the board does not lack worthwhile features, including two M.2 connectors and a U.2 connector, for hooking up plenty of high-speed storage. The board also has a nice array of internal fan headers (with auto DC/PWM modes), plus both front-panel and back USB 3.1 Type-C connectors.
Onboard wireless networking isn’t available, which is a little surprising, considering that the board is aimed at pros. On the other hand, you have that pair of M.2 connectors, should you want to pick up a wireless card in the M.2 form factor. And with dual Gigabit LAN controllers from Intel, wired networking is handled in spades.
One of the X299 SLI Plus’ biggest draws is its price. At $259.99, the motherboard lands on the low end of the X299-board price range. (The cheapest X299 boards we saw at this writing were hanging around the neighborhood of $220.) It isn’t the least-expensive board on the market, but with heavy-duty gaming boards pushing the high $300s, we can see how the X299 SLI Plus will get a second look from a range of shoppers, regardless of its Pro Series label.
The X299 SLI Plus has a tame, cloudy-black theme that lets the motherboard’s LEDs do all the talking. The board isn’t as brightly lit as some we’ve seen recently, so whether you like this design depends on what you want from your PC. If you’re building a workstation for an office that values style, the X299 SLI Plus will fit right in. The LEDs give the board a little spice without venturing into overkill territory.
Some gamers might want more bling shining through their case windows. MSI put slash-mark-shaped LEDs on the heatsink at the top of the board and the larger heatsink that cools the X299 chipset, which we like, but it skipped lighting in other prime locations, like between the memory slots and on the window-facing I/O cover. The board doesn’t scream “gaming” the way an LED-lit dragon image does, but we think the X299 SLI Plus’s lighting gear is better than it might appear at first glance.
For one thing, the X299 SLI Plus has an RGB header, giving you the freedom to add your own 5050 RGB strips (up to about three meters long). If we had to choose between onboard lights and the header, we’d take the option that gives us more customization options, any day. For another thing, the onboard LEDs are also RGB and customizable, thanks to MSI’s Mystic Light features.
The X299 SLI Plus features eight memory slots and an army of power phases, so the top half of the motherboard is necessarily crowded. That said, MSI did a nice job of keeping components away from the CPU socket. We tried several liquid coolers and tower coolers on the X299 SLI Plus without any interference, even from our bulky G.Skill TridentZ DDR4-3200 memory modules. (Many coolers designed for LGA 2011 processors will fit the LGA 2066 bracket.)
The eight memory-module slots support dual- or quad-channel memory configurations. Note, though: Whether or not you can go with a quad-channel setup depends on the specific Core X-Series processor you install. “Kaby Lake X” CPUs (like the Intel Core i7-7740X we used in our test build, or the Core i5-7640X we’re currently testing) limit you to dual-channel configs, while the “Skylake X” processors (certain other Core X Core i7s, as well as the Core i9 lineup, including the Core i9-7900X we just tested) can accommodate quad-channel ones. The slots support up to DDR4 4133 memory for quad-channel setups, and up to DDR4 4500 for dual-channel setups. In either case, the maximum supported RAM is a hefty 128GB.
MSI added a feature that comes in handy when you’re installing the processor and memory. Power on your PC, and a rectangular LED in the upper-right corner of the board (near the debug display) indicates the required memory configuration: red for quad-channel, and white for dual-channel. You should know whether you’re going dual or quad before you begin the installation, but we certainly don’t mind extra troubleshooting help.
The lower half of the X299 SLI Plus is also fairly crowded, thanks in large part to the sizable heatsink over the X299 chipset. The heatsink has three long LED stripes, along with a chrome MSI logo that catches the light nicely when the LEDs are on. As busy as the motherboard is, MSI made good use of its limited space, squeezing the two M.2 connectors between a total of six PCI Express slots.
MSI wrapped the first and third PCI Express x16 slots with steel, leaving the other two x16 slots exposed. We like MSI’s restraint here. The PCI Express slots are a prime target for motherboard makers looking to differentiate their boards, and we’ve seen some gimmicky slot covers. MSI went the other direction by protecting just the two expansion slots that run at x16 with a 44-lane CPU onboard. The steel adds extra support for holding heavy graphics cards, and bracketing just the two slots is enough, especially as Nvidia is limiting its GTX 1000 series “Pascal” cards to two boards in SLI. If you’re serious enough to go with a three- or four-card AMD CrossFireX configuration, we suspect it won’t be a problem spending a little more dough for a deluxe board with even more of the slots metal-braced.
Packed as this quadrant of the board is, it also carries two PCI Express x1 slots. MSI took advantage of the dead space behind the x1 slots by parking the two M.2 slots there. The lower slot supports M.2 devices up to Type-22110 (that is, 110mm long), giving you plenty of flexibility when shopping for storage. The upper M.2 slot handles devices up to 80mm long (Type-2280) and has a shield that covers your storage device to add a little bit of extra passive cooling, for M.2 SSDs that lack a cooling sink on top…
Both slots also support Intel’s Optane Memory, for caching data to gain speedier performance with just a hard drive as the boot drive. Most folks buying into the X299 platform, though, we suspect will be more than willing to splash out for a “true” SSD.
The only downside to this M.2 slot is that it’s bound to be covered by your graphics card or cards; once the first card goes in, you’ll need to take it out again to access the M.2 slot. That’s a minor inconvenience, but it makes us wish that the shield was designed to be interchangeable with the lower connector. We suspect users who plan to populate just one of the M.2 slots will lean towards the one they can easily reach (in a single-graphics-card system).
MSI put plenty of ports on X299 SLI Plus’ I/O panel. A USB 3.1 Gen 2 Type-C (10Gbps max) port gives the board some future-proofing, while five USB 3.0 and four USB 2.0 ports handle typical peripherals. The panel also has a PS/2 port and two LAN ports, handled by an Intel I219-V Gigabit controller and an Intel I211 Gigabit controller.
The audio ports are backed by MSI’s Audio Boost IV sound package, which features Chemi-Con audio capacitors and an audio-specific PCB layer, and offers a 120dB signal-to-noise ratio (SNR).
The first thing you’ll notice when you go to plug in your peripherals is that the panel has CMOS and BIOS cycle buttons. The Clear CMOS button can come in handy, but the more noteworthy button is part of MSI’s BIOS Flashback+ feature. With just the PSU connected the motherboard, you can update the BIOS by loading the update onto a USB flash drive, plugging it into the designated BIOS Flashback+ port (you can see it in the shot of the I/O plate above), and pressing the BIOS button. That’s an easy way to bring the board up to date. When you’re not using that USB port to update the BIOS, it acts as an ordinary USB 2.0 port.
MSI added some worthwhile internal headers, including a U.2 connector, which lets you install a PCI Express 3.0 x4 NVMe device using the interface, the biggest candidate being Intel’s 750 Series SSD. The board also features a new-style USB 3.1 Gen 2 Type-C connector for very new PC cases that have a front-panel USB 3.1 Type-C connector. (Most to date haven’t incorporated this cable yet.) You can see it pictured below…
Sandwiched between the U.2 connector and the USB 3.1 Type-C connector are six of the X299 SLI Plus’ eight SATA 6Gbps connectors. Like the U.2 connector, the SATA connectors face off the right side of the board, making for cleaner cable routing. The other two SATA connectors sit at the bottom-right corner of the board, facing upwards.
We don’t have any complaints about the way the SATA connectors face, but we wish that MSI had found a different location for them. MSI ended up putting the front-panel headers near the middle of the bottom edge of the board, well away from the right corner, where you’ll typically find front-panel headers. If your PC case has long front-panel connector cables, the new header location won’t matter. But if you’re dealing with shorter cables, we could see how it might lead to cable-management headaches.
Another feature worth pointing out is the dual BIOSes. Tanking the BIOS is about as inevitable as experiencing a fender bender, at some point; if you tool around with your PC enough, you’re probably going to end up in a BIOS pickle. On the X299 SLI Plus, you can solve the problem simply by flipping the switch that sits behind the U.2 connector. The switch enables the second BIOS, which should get your PC back on its feet.
MSI hit a home run with its fan headers, both in terms of quantity and placement. The motherboard maker put a total of six fan headers on the X299 SLI Plus. Three sit along the bottom of the board, while the other three are at the top. We like to see at least one fan header in the middle of the board (to give users more options for plugging in the PC’s rear exhaust fan), but given the crowded center, sticking to the upper and lower edges makes sense.
The fan headers at the top of the board are spread out. A system-fan header sits near the I/O enclosure for your exhaust fan, while the other two headers are closer to the debug display. One of these doubles as a pump header (supporting up to 2A) for your liquid-cooling kit.
MSI put two USB 3.0 headers on the right side of the board (one of which faces off the side for easier cable routing) and two USB 2.0 headers. Despite the gray ink (on a black PCB, no less), most of the header labels are easy to spot and read. MSI even put “USB” in white ink directly on the USB 2.0 header plastic itself, which makes them impossible to miss. We wouldn’t have minded if MSI had gone with white labels for all the headers, but we can’t complain.
Most of the other headers are the board are typical, like the audio and TPM headers, but there are a couple unusual additions. One of those is the Thunderbolt header, which connects to a cable that comes with PCI Express Thunderbolt add-on cards.