Quick question about PCIe ports and max number of cards

I am a computer animator so I have been hit pretty hard with the ugly end of the stick thanks to miners. Much needed graphics card upgrades will be underway whenever a card is available and I get it before a scalper or miner does. Contrary to what some may think, doing this professionally is time sensitive and for as good as the pay is, hardware is even more expensive, so as badly as I would REALLLY really love to drop 7k making a 3gpu 32 core thread ripper setup, doing it all at once is not super easy. That’s what I figured with external power sources. Yeah I have a 1200watt modular power supply and thankfully can have virtually as many GPUs as there are power outputs on the PSU, and I’m only half used up, so I should have room for 1 or 2 more cards. Now I definitely have a concern as to whether or not it is the best idea. With external power, would that still effect the mobo? I am running 2 GTX 1080tis right now no problem.... could a third card really cause me that much trouble?

Fair enough. Unfortunately the bad things make up 50% of the total purpose of forums. But in my case they have saved me more times than I can count. In this case I just need to find a solution. Once I get 1 or 2 3080 or 3090s that will still be a drop in the bucket in terms of the desired number of cuda cores. Granted, the “”desired”” number would be a whole farm to myself but that is a lot more money than I have use for right now so I will stick to the “more cards more better” argument. That or I win the lottery, and then, he’ll, render farm here I come