Best PC Hardware (Q4 2016) for a new build

If you search the forum for J1900, you will find the precise board that PCW tested and recommends, think it might be Gigabyte.

Make sure you choose one with a parallel port, or spend the extra cash you have on a Mesa 5i25 and 7i76 combo and latency becomes irrelevant.

There are lots of low cost alternatives out there.
My most up to date workshop machine is a GA-H81M-DS2 motherboard with dual core Pentium, which cost under £150 with a case and SSD.
It runs rt-preempt, with a 5i25/7i76 combo which cost a lot more than the computer

regards

After scouring the forum and the Linux world, I've just built a system using a J1900 gigabyte Brix attached via ethernet to a Mesa 7i76e. The real problem I faced was lack of graphics driver support in Wheezy so I've moved to Mint 17.3 and patched the kernel with the Peemptive core and compiled LCNC from scratch. You need a 64 bit PC to use the preemptive kernel for the mesa ethernet card.

As PCW states I found latency is terrible with the built in wifi card ( > 300000) so remove it and use a USB wifi dongle to talk to the world. PCW also had good results with a Zotac with similar specs. Latency is not an issue with the Mesa card and somewhere PCW said the Zotac was up around 120 usec which he was comfortable with. My Brix is around 60000.

I think the USFF PCs are a good solution if you are happy to use Mesa. My NEMA23 steppers are running faster and accellerating quicker than I ever expectedso I am very happy.

Thanks @rodq and @ArcEye,
I'll weigh either a Celeron, Pentium Haswell, or Core Skylate solution. I'm not convinced of the benefit of going with very old hardware for cost reasons. I do think the TDP of the J1900 is very appealing, and that would be my primary consideration looking there vs. the other two options. Skylake seems like a bit of a crapshoot, but then again the hardware could be recycled for some other use if it didn't work for LinuxCNC. One problem I am seeing with the J1900 solutions is they seem to be going out of stock/EOL, for example the GA-J1900N-D2H, which is the most appealing board that I could easily find.

On the control solution side, Teknic just officially announced their ClearPath SC motors. I knew they were coming, but didn't know how exactly they would be controlled. They will take direct software control over RS232 ( www.teknic.com/accessories-guide-sc/#sc_hub ). This will likely require some work, but this promises to drastically reduce cost/complexity for this type of setup. A 4 axis controller board is $50, and up to four boards can be daisy-chained from a single RS232 port.

The question is how difficult it will be to plug the Teknic libraries into Linux CNC.

Just checked the Teknic whatever, and i see no reason for going back in time and using RS232.
Then again that card will simplify things ONLY if using their drives.
Back to Linuxcnc, it can do things through rs232, but i doubt it will do actual real time control over it.

I dont think you could use the Technic SC drives with LinuxCNC, at least for coordinated axis motion control.
For example to start coordinated motion you need to use their special trigger scheme where they
preload trajectories and then send a "group trigger" since you cannot send different commands to multiple drives at the
same time (and their 1000 message per second limit means there would be at least a 1 ms delay
between separate axis)

That type of smart drive is ideal for things like tool changers and general (non real time) motion however

If you review the Techniks site carefully, the appropriate setup for LCNC on the page you linked to is the SD (step and direction) tab. Many of the other configs they show are for simpler industrial configs that do not do the whole motion control gamut encompassed by LCNC.Their MC series allows you to drop in servo motors into CNC applications already set up for stepper motors without the need to replace the stepper controllers with servo controllers. That is my fallback plan but currently my stepper based system is exceeding my design parameters so I doubt I will go this way.

But if you want to go to servos on a new build and are buying the controllers and the motors, there are many other options that will play with LCNC. Service and support in your part of the world is part of the selection equation.

In relation to using current hardware, the more important consideration in my view is settling on the PC interface to the motion hardware that replaces the thoroughly obsolete parallel port. This is where the Mesa ethernet cards such as the 7I76e and 7i77e fill the bill admirably. They bring a robust industrial environment to the equation without having to compromise on the number of inputs and outputs.

Don't stress that LCNC does not need the latest CPU to run on. Embrace that and put the money you save into the interface hardware.