Yet another mesa recommendation

I have a diy cnc which I use almost exclusively for pcb drilling and routing.

Currently it has a 5i25 with a gecko g540 and 3nm steppers on all axis.

Some time ago I purchased 2 leadshines 400w ac servos with 17 bits encoders, to replace X and Y steppers in order to improve rapids, since drilling jobs have lots of travels between points. they are rated at 3000 rpm max

Also have a 5um glass scale that will be fitted in the future in one of the axis, once all the rest of the conversion is done, to test the dual closed loop and if it goes as planned, purchase a seccond one

The Z axis will still use the 3nm stepper (maybe Ill upgrade it in the future) with a leadshine driver, but the 1605 screw will be replaced with a 1616 or 1620 to gain speed.

another stepper will be added shortly since I bought a ATC spindle and will need some sort of linear actuator to pick the drill bits.

So, the "I/O budget" is currently:

5 logic outputs for the steppers, 2 step and dir plus one enable
3 +-10v
5 quadrature encoders with index, 3 servos and 2 glass scales, but only 2 needed right now, so the others can be added latter with one of the remote serial cards
4 homing inputs
1 Estop
1 spindle enable and one 10v, in this case I might use a spare servo analog output


My first choice was a 7i77 and a chinese bob for the steppers, but mesa doesn't have it in stock and they will not be for another month

My current choices are:
Put the 5i25 to rest and go for
7i76e + 7i83 for $280
7i93 +7i33+ 7i37 at $247

use the 5i25 with 7i76 + 7i83 for $200, using some of the 76 inputs for the encoders feedbacks

I really like the Ethernet idea, however, I have read somewhere in this forum that its not match for pci speeds and since the servos have 17bit encoders and Im aiming at maximum speeds, just dont know if this will be an issue or not.

So what are your opinions? Will happily evaluate any other options you may think of

I think I would probably use a 5i25 (or 7I92M) +7I76+7I85S+7I83
The reason for the 7I85 or 7I85S is that you can't really use MPG encoders for motion
It might be better to wait for the 7I77

If the drives support velocity mode, you typically don't need more than Ethernet speed (1 KHz update rate)

Thank you PCW, as always, a very reliable answer.

Is there any difference in speed if I run the servos in position vs velocity?

Im aiming at getting maximum speed from them, but on the other hand, since this are my first experience with servos, I have read that they are much easyer to tune inside lcnc and for that they need to be driven in velocity or torque modes.