@Bts152 Please disable Game Mode and Game Bar, both features of Windows 10. You can reach the settings for each feature by hitting Windows key-i and choosing Gaming.
If that doesn't help, please go into Documents\Electronic Arts\The Sims 3, open the file labeled deviceconfig.log, copy the first 40 or so lines (stop where "Options" starts), and paste them here. This will show how the game is reading your hardware. The file lists your user and machine names about 25 lines down, but there's no other personal information.
@Bts152 Yes, I meant paste the 40 or so lines of text into a reply here. You could also attach the entire file to a post; either way works for me.
=== Application info ===
=== Rating info ===
GPU: 5 GPU Memory: 4 CPU: 3 RAM: 4 CPU Speed: 2496 Threading: 3
Adjusted CPU: 2928 RAM: 7985 Adjusted RAM: 7473 Cores: 4
=== Machine info ===
OS version: Windows 8 6.2.9200
OS prod type: 0
OS major ver: 6
OS minor ver: 2
OS SP major ver: 0
OS SP minor ver: 0
OS is 64Bit: 1
Brand: Intel(R) Core(TM) i5-10300H CPU @ 2.50GHz
Free memory: 4167MB
=== Graphics device info ===
Name (driver): NVIDIA GeForce GTX 1650
Name (database): NVIDIA GeForce GTX 1650 [Found: 0, Matched: 1]
Chipset: Vendor: 10de, Device: 1f99, Board: 09e11028, Chipset: 00a1
Driver: nvldumd.dll, Version: 18.104.22.16806, GUID: D7B71E3E-5CD9-11CF-CE67-EF291BC2D635
Driver version: 5206
Texture memory: 2048MB
Vertex program: 3.0
Pixel program: 3.0
Hardware TnL: 1
@Bts152 The game is using your Nvidia card, and rating it correctly (despite the fact that it's unrecognized), so that's not the issue. I understand that the screen filckers in fullscreen mode, but please try it and see whether you specifically get the same white lines or not. Even if fullscreen mode isn't a solution, it's still useful information.
Please also try playing in windowed mode at a resolution smaller than your screen, as in, something smaller along both dimensions than 1920x1080. Again, even if this isn't ideal, it's worth checking to see whether the lines are still there.
The reason I'm asking about fullscreen mode is that the flickering you've described can often be fixed by enabling vertical sync. While the v-sync option in the Nvidia Control Panel doesn't work anymore on laptops with dual cards, at least as far as I can tell, there is a tool that works for games that use DirectX 9, like Sims 3 does. Since it's a third-party download, I can't link it here, but if you're interested, let me know. Another player tested it a few weeks ago and reported that it worked well with Sims 3.
@Bts152 The outside tool isn't necessarily going to fix the white lines; the point was that if the white lines were gone in fullscreen mode, the tool might help with the flickering. Still, if you want to try, there's no harm in doing so. The tool is called D3DOverrider and is built on RivaTuner Statistics Server, which is reliable and widely used.
Did windowed mode on a reduced resolution help? I'm just wondering whether that makes a difference, even if you don't want to play that way permanently.
I’m fine with using windowed mode- it’s just that I need to get rid of those white lines that shows up on basically everything like skin, clothes and furniture
@Bts152 I understand the issue you're having and that you want to get rid of it. My questions are these:
Please let me know the answer to each of these three questions, and we can go from there.