Mesa (5i25/6i25)/7i76 vs 7i76e Comparison?

When looking thru the Mesa catalog for options for my next built, there are two options which seemed to stand out. The (5i25/6i26)/7i76 combo and the 7i76e. Both options are similarly priced. With the desire to use a VESA compatible mini itx case, the 7i76e is the ideal option. What I would like to know is: what are the performance differences between the (5i25/6i26)/7i76 combo and the 7i76e? Does the bus speed of the pci/pcie make a significant difference over the 100BaseT ethernet connection?

I would have to agree with Tommy. Aside from maybe different pin names, the connection between Linuxcnc and a mesa card is totally transparent to how its connected to the PC whether its via PCI or ethernet. The ethernet cards can drive steppers at 10 Mhz which will not be the limiting factor (eg. some other timing issue will prevent that speed from being achieved.)

The PCI/PCIE cards have a slight advantage _if_ you have unusual hardware and need a
faster than 1 KHz or so servo thread rate. This may be an issue if you are running bare PWM or
torque mode drives, but with step/dir systems or velocity mode drives, the default 1 KHz servo
thread is fine so the PCI/PCIE/Ethernet cards are all basically the same performance wise.

You can run up to about a 4 KHz servo thread with the Ethernet cards but this requires a fast CPU
while 1 KHz works on almost anything. The PCI/PCIE cards can run servo threads up to about 10KHz on
fast hardware.