Speed of loops on Win, RT OS, FPGA

[ceties]

Hi, this is general question. I am just wondering what are the achieveable speeds of a loop, lets say running simple PID. I saw a comparison but I cannot find it enywhere now.

I would like to know the aproximate speeds for
Windows OS
RT OS
FPGA

Thanks

[altenbach]

Here are some partial answers:

An older quote from here (The numbers are probably faster by now)

"With current technology, you can run PID loops up to 20 kHz using NI Compact FieldPoint controllers, 40 kHz with NI PXI technology, and up to 1 MHz with NI CompactRIO hardware when using PID functions based on field-programmable gate arrays (FPGAs). "

The answer for a regular OS is of course more complicated. How many CPU cores? What else is running on the computer, etc. How much jitter is tolerable? Also, on RT, the rate is reduced proportially if you add more PIDs, while on FPGA each can run independently at the full speed.