@VanDusensGirl In that case, I think it's definitely worth some testing to try to pinpoint the issue. The first suspect is still the PSU. Can you borrow one from a friend to test? The 1070 ti would need at least a 500W power supply, and the Titan 650W, to make sure the system gets enough power overall. It would be best to try both cards, if you can manage it.
If that's not possible, or if you'd rather be more thorough, thre's a simple way to monitor your hardware. Download hwinfo from here:
https://www.hwinfo.com/download/
You don't even need to install it if you don't want to—download the portable version, unzip it, and launch it directly from Downloads. (If you do want to install, be sure to click the green button, not the orange one.) Open the app, choose "sensors only," then click the icon that's a sheet of paper with a + sign to start logging. Take note of where the log will land, so you can find it later. Wait five minutes, then launch Origin and TS4, and play for 20 minutes, or until your computer restarts.
You can upload the log file to a third-party hosting site and link it here, or you can change it to a .txt file (just file.txt, not file.csv.txt) and attach it to a post here.