Monday, October 02, 2017

A little NUC on my desk


When my 8 year old computer, home built with a Core i7-920 processor, began freezing up randomly, a new generation computer was in order.  The only application I normally use that takes significant computing power is FlexRadio's Smart SDR for Windows that needs to control the Flex 6500 SDR transceiver.

Recent SSDR versions are much less demanding than they used to be, so maybe I could make do with a "downgrade" to a Core i5 system.  Intel processors divide broadly between "i3" (dual core), "i5 (dual core, with hypterthreading yielding 4 threads), and "i7" (quad core, 8 threads).  Of course, the later chips ("generations") in each category will be a lot more powerful than the earlier ones.

After some debate, I selected a Intel NUC (next unit of computing) tiny computer configuration in "kit" form.  You need to supply your own SSD (solid state disk) or hard drive and your own DDR4 RAM.  The NUC is available in quite a few versions, but I ended up with the Intel BOXNUC7I5BNH kit, which is a "7th generation" i5 box with room to add a 2.5 in. SSD or HD.

I installed a Samsung 960 EVO Series - 250GB PCIe NVMe internal SSD, which uses the (relatively) new M.2 interface and leaves the 2.5 in. bay free for the future.  Two 4GB DDR4 RAM chips complete the kit.  Assembly is trivial, if you're at all familiar with computer innards. Installing Windows 10 Home from a USB memory stick was quick. Transferring data and software from the old system was simplified by staging files onto an external USB hard drive.

After all that, we have a very fast little computer.  The Passmark benchmark comes out at 3,644, which is roughly 60% of the score of the old i7-920 with GT640 graphics -- but with half the cores and only on-chip graphics.  The NUC is happy to drive my two HDMI displays, although the second display requires a Thunderbolt/USB-C to HDMI adapter cable.  SSD I/O performance is blazing!

But what about Flex SSDR?  That's the primary app for this computer -- when I'm not using the Flex Maestro controller.  Here are some results:

Panadaptors |
window size |
CPU utilization |
Network Mb/s
1
1/4
15%
2.4
1
full
20%
2.7
4
full
33%
6.0
4*
full
44%
9.4
4*
1/4
36%
7.2
(* maximize spectrum frames per second and waterfall rate)

The worst case CPU load (44% across the 4 i5 threads) seems to be a comfortable number.  The Flex 6700, on the other hand, with its maximum 8 panadapters might have trouble, if that's your operating style.

The NUC handles the required load with capacity to spare.  It uses much less power to run and has only about 1/60 the volume of the old system, fitting easily on the desk.

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