ASUS B150 PRO GAMING/AURA Motherboard Review

Author: MAC
Date: February 8, 2016
Product Name: B150 PRO GAMING/AURA
Part Number: B150 PRO GAMING/AURA
Warranty: 3 Years
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Feature Testing: M.2 - PCI-E 3.0 x2

One of the big advancements of the Skylake LGA1151 platform was the fact that it brought the M.2 connector to the mainstream. Not only did it make this new storage connector available at a more reasonable price, but properly implemented too with a full speed PCI-E 3.0 x4 interface and support for NVMe SSDs. Regrettably, the B150 PRO GAMING/AURA falls a little short, its M.2 connector has been limited by a PCI-E 3.0 x2 interface. With that means is that instead of having a theoretical maximum bandwidth of 4GB/s, it is limited to 2GB/s. While this might seem more than adequate for most PCI-E SSDs, as you will see below it did end up being a bottleneck.

We selected the Samsung SSD 950 PRO 256GB as our test drive because this next-generation NVMe PCI-E SSD combines Samsung's newest UBX controller with its industry-leading 3D V-NAND and is capable sequential read speeds of up to 2,200MB/second and write speeds of up to 900MB/sec.

One of the ways that we will be evaluating the performance of a motherboard's M.2 interface is by verifying if it is capable of matching these listed transfer rates. The other is by checking to see how it performs compared to the SSD 950 PRO installed onto a ASUS Hyper M.2 x4 expansion card plugged directly into a PCI-E 3.0 x16 slot. Since the B150 PRO GAMING/AURA's M.2 connector is limited to PCI-E 3.0 x2, we know that the expansion card will outperform it, but it will see interesting to see by how much.

M.2 x2 vs PCI-E x4

As can see, the M.2 connector on the B150 PRO GAMING/AURA definitely bottlenecked our Samsung SSD 950 PRO. While this M.2 x2 interface has a theoretical maximum transfer rate of 2GB/s, the sad reality is that bandwidth overhead reduced this to under 1.7GB/s. As you can see on the right, when placed in the Hyper M.2 x4 expansion card and unencumbered from bandwidth limits, the SSD was able to achieve read speeds of a little over 2.2GB/s.

While transfer rates are obviously an important metric, we figured that it was also worthwhile to take a peak at instructions per second (IOPS) to see whether there was a bottleneck there as well:

M.2 x2 vs PCI-E x4

While there is still a performance bottleneck - as evidenced by the 39% higher 16MB read IOPS visible in the PCI-E x4 benchmark - the overall differences are minor since most of these tests aren't the type of large sequential IO transfers that could max out the interface.

So yes, the B150 PRO GAMING/AURA will hold back your new M.2 SSD if it is capable of transfer rates over 1700MB/s, but it won't have any effect when it comes to the small file transfers that these new NVMe SSDs exceed at.

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