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Aaron N. Tubbs

Dragon chaser.

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I want to love the Intel NUC form factor, but it’s just not working out between us. I acquired one of the original generation NUCs; it was great for a few weeks and then it melted. Thermal issues in the chassis (at nearly idle) destroyed the SSD. They came out with a BIOS patch for this later, but the patch amounted to running the fan full bore all the time and still couldn’t effectively evacuate enough heat from the chassis in practice. There were some other problems with this model, notably the lack of USB 3 ports and problems with the NIC performance degrading when the adjacent HDMI port was in use. Still, it was a first-generation product and I wrote off the issues. At the end of the day I was still in love with the form factor and performance. It was not blazing fast, but it was fast enough for my routine needs.

Next I picked up a third-generation Intel NUC. It worked fine as my primary server for several months now until today. For some reason the TSC spontaneously developed massive jitter problems, and linux disqualified it as a time source. This would be fine except the only other options available to Linux installed on this platform are jiffies and jiffies skew at a rate that even NTP can’t correct (my skew is several seconds per second at this point). A server that can’t keep time is more or less useless, so now I have another dead NUC. This is far more frustrating than the last time.

I have one of the original Gigabyte Brix models as well, and it still seems to be operating properly. Inexplicably it’s even smaller than the NUC itself, comes with less plastic (perhaps better thermal behavior) and onboard wifi (rather than a paid extra).

So, I was impressed by Gigabyte to this point and they announced their 4770R, which added room for a 2.5” drive, seemingly more thermal envelope, and a beast of a CPU compared to the previous offerings. The i7-4770R is a bit of a boutique part, but it’s got four physical cores, as bunch of cache, and decent clock/turbo performance. While I’m not often CPU-bound, having access to a little more muscle definitely comes in useful. Even dumb things like building this blog take minutes on my third-generation NUC, and take seconds on a faster CPU.

The problem is, the Gigabyte 4770R does not have the ability to actually manage the thermal envelope of the i7-4770R. The best it can do is make a ton of noise spinning an obnoxiously small fan (read: loud) to try to keep up before detuning the CPU. Given my experience with the NUCs to this point, running a hot chassis (especially given that that’s the reason why the 4770R was appealing: having access to more compute power) sounded like a good recipe for more lumps of dead parts.

The funny thing is I still have a perfectly functioning Dell T110 server. Here are its problems:

  • It’s huge
  • It’s many years old
  • It’s slow (an early generation Xeon) … despite all the fancy cache, Xeon-ness, and cores, in practice it’s slower than the first generation NUC
  • Its IO is slow (1st generation eSATA)
  • It doesn’t play particularly nice with solid state drives

So for my most recent server build, I got back into doing something I told myself I’d never do again: Building a PC. For about the same budget as a well-equipped NUC, I got a mini-ITX case & server motherboard, some ECC RAM, a zippy Xeon CPU, a modern I/O subsystem, full-size Samsung SSDs, two bondable Intel NICs, and KVM over IP + remote management/power. It’s got a bunch of nice and quiet 120mm fans, the disk performance is stupendous, and I suspect it will be a bunch more reliable than my experience with the NUCs. Pegging CPU, memory allocation, and disk IO doesn’t even raise the raise the thermistor temperature on the motherboard and doesn’t cause the fans to throttle up.

The downside is that even for a mini-ITX board and case, it’s about 40 times the size of a NUC. It seems like there are two ways to resolve this, but neither are particularly practical. The first is to build the NUCs out of more exotic (expensive) materials. If the entire sled was made of a bunch of copper instead of plastic, more effective thermal evacuation seems likely. The other approach is to dramatically decrease the TDP they’re stuffing into these chassis; that is happening, but far too slowly. The Xeon in my server build has a TDP of 77W versus the i5-5250U (in the newest, fastest NUC)’s 15W or the i7-4770R’s 65W. But, the Xeon delivers more computing horsepower than either and is a pretty cold chip under load in a mini ITX chassis.

At the end of the day, this is probably the last generation of building a server anyway – increasingly my needs could be served by an off-site virtual machine. But, for now my hope of a long and happy love affair with the NUC form factor seems to be dead.