Just probing possibilities at this point.  I made the move to USB (MOTU 8M) over a year ago and had Roseberry rebuild my DAW - very happy with it!  Now I have two Lynx L22 PCI cards (not PCIe) and the LS-ADAT daughter card that I am wanting to use or sell.  I used them for years on an Intel DP35DP motherboard which only allows for 8GB RAM.  That's being used for the home computer ATM (Windows 10 running fine on it - milking it for all it's worth).
 
My church (employer) kindly provided me with a computer that has a single PCI slot - ASUS Q170M-C motherboard and the L22 has worked well for a year now without issue but I may be replacing it with a low end USB interface with MIDI I/O as the L22 seems overkill for my office use.
 
I'm wondering if it would be viable to build a VSTi machine to offload the overhead from my new home studio DAW and use it solely to host virtual instruments ultimately giving me the ability to orchestrate/arrange and produce entirely ITB.  Not a need ATM but thinking it could benefit me in the long run and be a viable use for the Lynx cards at a reasonable price.
 
Questions:
1. Besides the aforementioned, any suggestions on specific motherboards that still provide dedicated PCI slots (non-bridged)?
2.If used to host VSTi's, I assume that RAM is more important than CPU.  Can I get by with a lower level CPU (Intel/AMD) and just max out the RAM?
3. Connecting by CAT5 will I still need to output audio via the soundcard back to my DAW right - not done over the data cable is it?  I can do that digitally of course via ADAT.
4. Is it a worthy project and worth the hassle to do? I know I'll have to answer that but would you do it?
5. Or perhaps a mastering or mobile rig?
6. Other thoughts/advice/suggestions?
 
Thanks in advance!

for me it always came on my mind but in practice it always failed to happen,2 comp's linked each doing its thing i mean. splits,adapters ,sync etc... so one PC is enough  ,more so,in the last few years i am giving the analog world more credit and using outboards so i am trying to minimize the use of ITB for the benefit of "noisy circuitry".
anyway,to ease the cpu work on one pc you can merge files with the changes of the vst FX's after you decided its the right move,and save the original files with a comprehensive name if you want to roll back.usually works well with dynamics ,EQing etc...
reverbs and highly demanding cpu FX with complicated algorithm  can be recorded to seperate channel and added in percentage to the mix.
vst synth's can be treated the same with an audio file recorded to the DAW.