LinuxCNC and AMD APU?

Hello everyone,

I am considering using LinuxCNC in the future and i was wondering if using an AMD APU (like AMD Ryzen™ 5 2400G) was possible and won't be a problem for the real-time processing?

I can't comment on the on Ryzens themselves but the following is an issue a user ran into lately with a UEFI only boot system.
If your MB doesn't have a Legacy\CSM ie: UEFI only you will run into installation problems with RTAI and will only run as an essentially a single core system. RTAI has no support for UEFI, that is the issue simplified.
With RT_PREEMPT you may have to add efi=runtime (this took almost a full day googling to find out, this included rebuilding the kernel a few times trying a few different options) to the kernel command line or you will run into problems with 4.9.106-rt44 kernels. I can't say for sure about earlier RT_PREEMPT kernels.
If you are able to boot via Legacy\CSM module you should be ok, but if you want to dual boot with Windows 10 there maybe issues.

Hopefully the devs are aware of and addressing this issue for the next round of ISOs.

But in saying all that, 2nd i3/i5/i7 systems are perfectly fine.
Someone else was asking about a PC for Linuxcnc a day or 2 ago and Tommylight supplied a list of known ex Office class machines that will work absolutely fine.

Many users, my self included, are having great reults with something like Asrock J3355B itx, with the J4015 series they are UEFI boot only.
Depending on what you are using to interface to your cnc machine latency figures can be pretty flexible.

It's starting to look like older PCs maybe the better option at this current moment. I've even tested some 2010 circa AMD MB and Radeon card combos and seen pretty good results.

Disclaimer: I am not always right, so do some extra research post what you find and even ask more questions, wait for other opinions and if what I say is bollox tell me I'm a piece of excrement that talks even more excrement.

Hi,

Thank you for the precious information, the motherboard (B450 I Aorus Pro Wifi) i am planning to use has definitely Legacy\CSM support so i will definitely give it a try.

I'm not surprised to read that old hardware work better, since RTAI is built upon Debian 7 (Wheezy) which is indeed very old.

Thanks again for your answer and stay safe during that human malware pandemic outbreak

blackmennewstyle wrote:

Hi,

Thank you for the precious information, the motherboard (B450 I Aorus Pro Wifi) i am planning to use has definitely Legacy\CSM support so i will definitely give it a try.

I'm not surprised to read that old hardware work better, since RTAI is built upon Debian 7 (Wheezy) which is indeed very old.

Thanks again for your answer and stay safe during that human malware pandemic outbreak

No worries mate, and like I knew tommy would come to the rescue.

tommylight wrote:

Yesterday i got a shiny new AMD Ryzen 5 3600 i think with an Nvidia 1660 Super on it and all the bells and whistles and i am pretty sure it has a B450 main board, so i can test it right about now. Sorry was busy playing on it, have not played anything in over 15 years.
Results later.

Congratulations for your brand new Ryzen 3000 chip, i got myself the AMD R9 3900X on my home/work PC. Amazing series of chips, you will definitely enjoy the R5 3600 a lot.

My plan is to use the AMD R5 2400G with a B450 Mini-ITX motherboard (which has only one PCIE-Slot) in a DIY router wall cabinet which will contain everything: spindle inverter, stepper motor drivers, CNC router board, power supplies, motherboard and ton of ventilation.

I am hoping to use the onboard AMD VEGA 11 graphic chip built-in the AMD R5 2400G as a graphic card and use the only available PCIE slot on the motherboard for a PCIE parallel port board.

Have fun with your testing, i will report my experience as soon as i will receive and start to use my motherboard.

I have all my bits, so to speak, in a 19" rack cabinet.

Just make sure you have the filtration to match the ventilation, otherwise it maybe moot having all the ventilation.

My MB is in a 1U chassis, Mesa 7i92 & 7i76 with 5v PSU & one 12v psu are in a 2U chassis and the Stepper drivers & 48v are in a 3U chassis, without a lid on the 3U only, I can run the Mill all day in the Aussie summer in poxy hole that the Estate agent refers to as a 1 car garage (tho if you manage to get a car in there getting out of the car is an issue) and haven't seen a issue with heat. Apart from the back of the cabinet and a vented panel in the front it's all enclosed. Of course I don’t' have a VFD in there, but the VFD for the Lathe doesn't create an over abundance when pushing the 1HP motor.
But I do know some people really like their fans.

BeagleBrainz wrote:

I have all my bits, so to speak, in a 19" rack cabinet.

Just make sure you have the filtration to match the ventilation, otherwise it maybe moot having all the ventilation.

My MB is in a 1U chassis, Mesa 7i92 & 7i76 with 5v PSU & one 12v psu are in a 2U chassis and the Stepper drivers & 48v are in a 3U chassis, without a lid on the 3U only, I can run the Mill all day in the Aussie summer in poxy hole that the Estate agent refers to as a 1 car garage (tho if you manage to get a car in there getting out of the car is an issue) and haven't seen a issue with heat. Apart from the back of the cabinet and a vented panel in the front it's all enclosed. Of course I don’t' have a VFD in there, but the VFD for the Lathe doesn't create an over abundance when pushing the 1HP motor.
But I do know some people really like their fans.

Your setup looks amazing. I will make sure to do not under-look the filtration. Thank you for all your inputs

tommylight wrote:

Not much luck with it, it has a latency of over 400000!
The main issue is there is no way of disabling hyperthreading, the thing that i utterly hate, it never did anything to improve computing, but it is still being used as a holy grail !
Will have to do some more tests but it does not look good, to much power saving and throttling core jumping, DDR4 with to much latency, etc etc.

Oh snap. What motherboard are you using? Maybe i can help you out for disabling hyperthreading. For Intel, it's often called disable SMT while for AMD it's called disable CMT. But sometimes, the motherboard manufacturers mix up both naming. Try to search for both naming in your motherboard BIOS.