Dell 990 SFF is jitter of 8200ns is OK?

Seems some posts on machines are rather old, with very old versions of kernels etc.

So anyway, I picked up a 3 year old Dell 990 SFF with a quad core 3.1Ghz CPU and 4gb of ram for $100NZD (about $60US), I have added a pci-e parallel port card (still trying to test to see if it actually works with linuxcnc, but Dmesg says yes its detected). So is a max jitter of 8200 OK? I have set 8000ns assuming so? Not sure if this is good, bad or average?

If its not very good I can look around for another machine. Also does things like turning off multi-core in the bios still apply?

This machine will run the CNC and nothing else so its bios etc can be tweaked to suit.

8200 ns maximum base thread jitter is quite good and means you can likely generate
step pulses faster than your step motors/driver can spin

Cool now I just have to prove the aliexpress pci-e card really will drive the driver(s) and hence the motor (still awaiting parts from china)

So is a max jitter of 8200 OK?

Yes, as PCW said, but did you stress the machine by running glxgears, etc. a run the latency test for an extended time?

Rick G

Rick wrote:

So is a max jitter of 8200 OK?

Yes, as PCW said, but did you stress the machine by running glxgears, etc. a run the latency test for an extended time?

Rick G

Nope, all I wanted to see at this stage was if this SFF (small form factor) box would be good enough and not waste hours if it was hopeless.

Otherwise a) no need at this bench test stage. b) it will be a dedicated machine just for CNC so I might even strip out stuff so there is nothing left to "play with". c) glxgears is a GPU benchmark when I know the onboard wont run that well and I know it wont be multi-tasking. Now once I get closer to actual running, yes I will do a proper test as a check.

Nope, all I wanted to see at this stage was if this SFF (small form factor) box would be good enough and not waste hours if it was hopeless.

Really will not know that until you run a proper test.

Rick G