So I'm pulling an old monitor out of the closet for a quick spat of productivity.
My main is 16:9 - 1080p - 144Hz
The old one is 16:10 - 1680x1050 - 59Hz
Can I run these monitors with their respective setting at the same time?
I don't much care about the quality differences. The extra monitor is for real estate - so main monitor is for the project and side monitor is for sources and pulling files and whatnot.
Can I do this in Nvidia Control Panel, and if not, do I need a different software?
Yes, as long as you can plug them into the card.
You're overthinking this, it's what they are supposed to do.
As said above, you can run any monitors together you want.
You don't even need Nvidia Control Panel, just right click on your desktop > Adjust Screen Resolution > Extend Displays
Adjust how it's best for you and have at it!
For reassurance/reference. I use a 4:3 9.7" 67hz iPad screen and a 16:9 27" 60hz Iiyama prolite X2783HSU together.
Multi monitor will take what ever you cannplug into it. It is only when stretching the one image or game across multiple monitors in sync that you need specific matching monitors, and even then I believe this is only an nVidia issue, AMD can mix and match resolutions and all sorts in game.
So yes it will work fine.
40 inch 4K TVs are extremely cheap these days. Do yourself a favor and buy one, it will be the best thing that happened to you since your first dual monitor setup. Now you can have 4 screens without bezels
i can run 3x 1080 and a 4k monitor all at once no problem with minimal finagling. just plug it in.