@ml1837 - There are two things I'm not seeing mentioned in your description. You have sought and obtained formal game recognition for your Nvidia 1650. but have you also addressed the 32 MB texture memory override? This doesn't hit all players on modern cards, but its impact could be significant if not tended to. If you would like some simple instructions to fix that, please copy and paste the first 40 lines or so of the file called DeviceConfig.log into a response to a PM that I will send you so we can confirm that your card is recognized correctly and see whether or not this needs to be fixed.
The other issue is actually much more important. TS3 being an older game has no functional built-in fps limiter and requires at least vertical sync, triple buffering, and frame rate capping set up on a profile for the TS3.exe executable by way of the Nvidia Control Panel especially for more powerful GPUs. Sometimes, quite often, an extra tool is required to lock things in. To see the actual frame rate you are getting in-game, ctrl+shift+C to bring up the cheats console, type fps on (enter). As you play and move the game camera around, the displayed fps rate should never exceed the refresh rate of your monitor/screen. Most are 60 Hz, so the goal for an upper limit should be 60 fps. To make the display go away, cheats console again and type fps off (enter).
It should also be noted that slow to render scenes will be made worse by clearing the game's cache files. We usually recommend clearing them on a regular basis anyway, and strong enough systems should recover the first time these scenes are rendered certainly better than you have described. But although the game becomes healthier for the cache clearing, and it's essential if one is working with adding new content and/or the Mods Framework, it doesn't actually help things in this regard.
