Looks like I should have been clearer with my post, sorry.
In the past Ive worked with LV on Windows, RT Desktop PCs, myRIOs and different cRIOs. Ive chosen Windows for this application because it should be fast enough and because of the development overhead needed for the FPGA Dev and so on. Also my application is more complex than the solar panels, but those explain my central problem (read - calc - write, no chance of writing or reading multiple data points instead of single DBLs because only the next value is known).
Getting more performance out of my code is my goal now, again Im sorry I didnt make that clear in the first post. I know the PSUs arent really quick, thats okay. The data sheet states rise and fall times for the outputs in the range of 2ms to 50ms (depending on the load). Id be perfectly happy when the code reading the voltages and feeding the PSUs is as fast as that.
Microcontrollers certainly would work but again that would take to much time now (and the simulation is only the first step in the project, later its the 'real deal' when I know I wont break something).
Ill try to build a minimal VI that shows the problem tomorrow to post here, then we can be more specific. For now Id like to know what the general approach would be here. Would the code be significantly faster if I read all Channels in parallel (with 1 daqmx read), calculate everything and write the values with 1 write instead of single DBL reads and writes encapsulated in multiple VIs (Overhead)? Could the USB connection (cable quality, length, USB hubs) make a big influence? Would an Ethernet Chassis be faster? Is there a way to speed up reads and writes in the cDAQ?