The best computer for latency i came acros.

After testing and working with a looooot of different laptops and desktops, a friend gave me a Fujitsu Siemens Celsius workstation so i decided to do what i always do when i see or get a computer, start Linuxcnc and see how it does. Well, i am glad i did since i was amazed at how good and how stable it was (although Linux Mint does not start from the RAID 0 setup, Ubuntu 10.04 starts and runs without a hitch).
Take a look, i did do a 4 hour test while actually using it, it was the same result but i do not have a picture of it since i gave the workstation to my brother and he promptly installed windoze on it.......what a pity !!!

Oh it was a dual 4 core xeon with 16GB of RAM and 2X80GB hdd in a RAID 0 setup when i took that screenshot, running stock Ubuntu 10.04, linuxnc updated to 2.7, had a HD movie playing on media player, and a 1080p video on youtube, and 15 glxgears.

Nothing ???
I thought a computer that does consistently under 3000 ns latency would be the holy grail of LinuxCnc for software stepping, or did i miss something ?
More info.
I did run it for several hours with 15000 and 18000 ns in the ini file for base thread and i did get occasional error at 15000 when playing youtube hd video, but never at 18000 so i connected an encoder with 100 cpr directly to paraport and adjusted the speed of the servo motor with a voltage regulator and it did count without a hitch up to 7900 rpm for long periods of time (15 to 20 minutes at full speed) and never got any error. Theoretically it will count at 8330 rpm, but i had a limited voltage so i could not go further with that setup.
This practically means, with a 1000cpr encoder it can do 833 rpm, 500cpr will do 1666 rpm, 200cpr ( i have plenty of 200 cpr encoder attached to servo motors ranging from 50 to 200w) 4100 something rpm, while a 2000 cpr will go only to about 410 rpm.
I have to build some nice pwm drives before i get that computer back in september, and see how it does at running 4 or 5 axes at the same time. I am pretty sure it will do just fine, since i did have a similar setup with 4 axes a while back but on a computer with 100000 latency so i could use it at 750 rpm max with 200 cpr encoders.
time for bed, 2:36 am here.
tom

Wirewrap wrote:

What is the brand and model of the motherboard in this PC?

It is OEM fujitsu-siemens workstation, search eBay for Celsius workstations, must be plenty there.
m.ebay.de/itm/Fujitsu-Siemens-Celsius-R6...862845649?nav=SEARCH

m.ebay.de/itm/Fujitsu-Siemens-Celsius-In...987401517?nav=SEARCH

Prices range from 130 to 300 euro for the silver older one, that is what tested. Mine had no paraport but an add-on PCI card with netmos chip.

It is best to start a new topic with a new and different question.

JT