Networking and Storage Performance

We have recently started devoting a separate section to analyze the storage and networking credentials of the units under review. On the storage side, one option would be repetition of our strenuous SSD review tests on the drive(s) in the PC. Fortunately, to avoid that overkill, PCMark 8 has a storage bench where certain common workloads such as loading games and document processing are replayed on the target drive. Results are presented in two forms, one being a benchmark number and the other, a bandwidth figure. We ran the PCMark 8 storage bench on selected PCs and the results are presented below.

Futuremark PCMark 8 Storage Bench - Score

Futuremark PCMark 8 Storage Bench - Bandwidth

The MZVPV256 is the first NVMe SSD in the M.2 form factor. Given its PCIe 2.0 x4 link (the controller supports PCIe 3.0, but the unit connects to the PCIe 2.0 lanes in the Broadwell-U package) and the advantages of NVMe over AHCI, we expected our configuration to lead the storage charts. Our unexpected results made us run a couple of other artificial benchmarks (reproduced below).

The results from ATTO and CrystalDiskMark matches the specifications (accounting for the downgrade of the host link from PCIe 3.0 to PCIe 2.0). After discussion with Samsung, it turned out that the performance difference was due to the Microsoft NVMe driver creating FUA (Force Unit Access) I/O write commands. These FUA commands bypass the DRAM cache on the SSD and directly write to the flash, increasing the response time and also lowering bandwidth. For the same access traces, this situation does not happen with the Microsoft AHCI driver.

We observed something similar with the Intel SSD P3700 NVMe PCIe drive. With the Microsoft NVMe driver, the benchmark reported storage bandwidth around 320 MBps, while the Intel NVMe driver bumped that upwards of 500 MBps. So, we can conclude with a high degree of confidence that the Microsoft NVMe driver needs some fixes.

On the networking side, we restricted ourselves to the evaluation of the WLAN component. Our standard test router is the Netgear R7000 Nighthawk configured with both 2.4 GHz and 5 GHz networks. The router is placed approximately 20 ft. away, separated by a drywall (as in a typical US building). A wired client (Zotac ID89-Plus) is connected to the R7000 and serves as one endpoint for iPerf evaluation. The PC under test is made to connect to either the 5 GHz (preferred) or 2.4 GHz SSID and iPerf tests are conducted for both TCP and UDP transfers. It is ensured that the PC under test is the only wireless client for the Netgear R7000. We evaluate total throughput for up to 32 simultaneous TCP connections using iPerf and present the highest number in the graph below.

Wi-Fi TCP Throughput

In the UDP case, we try to transfer data at the highest rate possible for which we get less than 1% packet loss.

Wi-Fi UDP Throughput (< 1% Packet Loss)

Recent driver updates have enabled the Intel AC726x solutions to perform up to their advertised potential. Users facing issues with them are urged to update their drivers as well as router firmware in order to take advantage of the capabilities. The Broadwell-U NUC (NUC5i5RYK) uses the same Intel AC-7265 2x2 802.11ac soldered M.2 Wi-Fi card as the NUC5i7RYH. So, it is not surprising that the TCP and UDP throughputs are similar for the two systems.

Gaming Benchmarks HTPC Credentials
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  • Antronman - Tuesday, April 21, 2015 - link

    Since when do monitors draw power from the device they're connected to anyways?
  • eanazag - Tuesday, April 21, 2015 - link

    Same response as close.

    Additionally, you want to have a power supply that can provide more juice because over time they lose the capacity to provide the highest specified wattage. If you have a device that routinely hits the max spec, you will experience some kind of failure. I'd rather see a 90 Watt charger. There were at least 3 USB slots I could see and they can pull at least 5 Watts. Additional components can pull more electricity too; like a 2.5 inch drive and the M.2 SSD. Maxed out the 65W adapter doesn't have a lot of wiggle room.
  • rhx123 - Monday, April 20, 2015 - link

    I'm sure the NUCs are getting uglier each time. The all black Ivy Bridge NUC was by far the best looking of the lot.
  • CaedenV - Monday, April 20, 2015 - link

    So I am curious about 4K support. This thing purports to have 4K display support, but I wonder how well it works. In another year or two it will be time to upgrade my wife's desktop and I really want to get a slick little NUC (or NUC-like) device paired with a small-ish (35-45") curved 4K display/TV. All it needs to do is web browsing, office, UHD video (h.265, Netflix 4K and youtube 4K), and upscaling our digital library of our ripped DVDs and BluRays (h.264 and h.265) to 4K playback. It does not need to play games, or rather can stream games via the home network from the 'real computer' in the basement which should have 4K game support in a few years.

    Any thoughts if this is realistic on this model? Will the technology be there in this form factor in 2 years? Or should I be looking at one more home-built machine for my wife's desk? I would really like to get her something small and fanless... or at least low-power enough to run fanless most of the time.
  • ganeshts - Monday, April 20, 2015 - link

    Something like the NUC will be working great in the next generation or so. This one has 4K support, but not HDMI 2.0 - Refer to our earlier piece on why most PC platforms are not ready for the 4K era yet :
  • xchaotic - Tuesday, April 21, 2015 - link

    'or rather can stream games via the home network' in uncompressed 4k???? that way more than even fiber can handle
  • extide - Thursday, April 23, 2015 - link

    He never said uncompressed 4k...
  • PICman - Monday, April 20, 2015 - link

    Ganesh, what is this 'realm of reason' of which you speak so frequently? What lies beyond the 'realm of reason'?
  • nathanddrews - Monday, April 20, 2015 - link

    Further confirmation that Broadwell is a big fizzle.
  • Flunk - Monday, April 20, 2015 - link

    Ticks generally just update the tock, so that's no surprise.

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