Any benefit to a RT specific Network card with a Mesa 7i76e

I'm looking at building some purpose built PCs for the project I'm working on. The original "development" PC I used was one of those Chinese industrial PCs with an Intel mobile I5 with a Mesa 7I76e, but I may switch to a 7i96 Since the former is overkill with IO. That worked fine but for reasons unrelated to real-time tasks or motion control, I have to use a better desktop processor and I'm preferable to AMD anyway. Mini-ITX mobos with dual NICs are rare so I'll have to drop in a separate NIC. I'm noticing RT specific cards that are pretty much compatable with all RT Ethernet protocols (Sercos, Ethercat, Profinet). Seems as though there is some support for all of this in Linux/LinuxCNC but I'm just starting to research this. I'm not using any of these protocols for anything but I'm Just wondering if there's an advantage to this type of card over just a decent standard NIC.

I dont think there is any real benefit to these "real time" cards for running Mesa Ethernet motion cards
that use plain vanilla UDP.

As long as you choose a card with a Intel or Realtek chip, you should be fine

OK so that said,

Is a mesa ethernet card realistically slower than something running on sercos or profinet? So far for the intended purpose I use the 7i76e for it's fine even if there is some sort of delay. I still see delay errors in LinuxCNC after slowing down the servo thread sometimes but it may be from high processor usage from another app.

I may instead use a 7i96 to replace the 7i76 since I don't need all of that I/O and may use this 7i76e and PCI on a mill conversion to send s&d probably to some clearpath servos. It'll be dedicated so the CPU usage from outside sources wouldn't be an issue.

Is there any firmware readily available to change one of the step & direction outputs to PWM? I've seen mention of it somewhere but I recall it being something you had to write yourself.

If you get real time errors, it not typically related to CPU usage but rather interrupt latency in the system
(often because of video or CPU power management). You can usually fix these errors by:

1. Making sure that all power management options are disabled in the system BIOS
2. if you have Intel video, disable the video power saving options in grub by setting these options:
i915.enable_rc6=0 i915.enable_dc=0
3. setting idle=poll in grub also helps sometimes
4. if you have a Intel Ethernet MAC for the realtime connection you need to disable
IRQ coalescing (using the ethtool utility)

Also for Preempt-RT, faster CPUs typically help ( One test machine using a H97+G3258
motherboard runs LinuxCNC+Ethernet reliably at 4KHz when using the computer to compile LinuxCNC/ run Youtube videos etc )

There is firmware/source for the 5i25+7I76 that has 4 stepgens and one PWM/DIR channel, it would be easy to compile a
7I76E bitfile with a variant of this pinout file.

The Ethernet latency is not limited significantly by the FPGA card, the host is the issue