Is the X99S SLI Plus the best solution for budget buyers? MSI thinks so, and put quite a bit of technology into this product to prove its worth. We’re still trying to figure out how one manufacturer can add four two-lane PCIe 3.0 switches to enable three-way SLI on Intel’s Core i7-5820K, while all of its competitors believe this is too costly for an entry-level X99 motherboard. As if anything X99 can be classified as entry-level.
But MSI doesn't stop with three-way SLI support. The company also adds a couple more switches to enable PCIe 3.0 x4 M.2 SSDs, or a graphics card in the fourth slot and PCIe 2.0 x2 M.2, or SATA 6Gb/s x2 M.2. That’s a lot of M.2 options. And users who don’t like M.2 can still get top SSD performance in an off-motherboard drive via SATA-Express, which is also missing from competitively-priced products. You can’t run SATA M.2 and SATA-Express, or run the M.2 slot in PCIe 2.0 x2 mode with SATA-Express, since those connections are shared, but even high-end boards with both interfaces have that restriction.
So, does this make the X99S SLI Plus a high-end board at an entry-level price? The six added-in USB 3.0 ports might have us thinking this, had we not already been blown away by all the PCIe 3.0 interface options. MSI even equips the board with twice as many DIMM slots as its closest competitor. It appears the only high-end features we don't get are a “Port 80” status code display and a secondary network interface. Those value-adds aren't missed much. We also aren't bothered by MSI's use of a previous-generation ALC892 codec where competitors have upgraded to the ALC1150.
Two final things that are missing (though not from the motherboard itself) are the second SLI bridge required to enable three-way SLI and 50MHz. Wait, what? In overclocking, the X99S SLI Plus came up 50MHz shy of most high-end boards using the same settings. Then again, so did its closest competitor. On the other hand, this is also the only moderately-priced motherboard to support our memory at data rates beyond DDR4-3200.
Performance-per-dollar appears a perfect match between the X99 Extreme3 and MSI’s X99S SLI Plus. But this chart is based on the running price of both products compared to the average of all 12 X99 motherboards we’ve tested in the past six months. If we were to instead use the temporary promotional price of $179 listed at Newegg, the X99S SLI Plus achieves a supreme value rating of 141%. Oh, and if you believe in rebate cards, Newegg even offers one for an additional $20 discount.