Constant flashing and lag spikes.

sproutedpup​  Before spending any money, I would suggest taking the computer to a repair shop where someone could install a new GPU to test with.  While it's very possible your current card is dying, you don't know that without testing, and it would be a shame to spend money to fix the wrong problem.

As for a newer GPU, what price range are you thinking of, and do you want a new one or are you willing to buy a used model?  I can have a look at what's available in your country if you want.  I would absolutely not pair a high-end card with your 1700X CPU, since you'd just see bottlenecks, but a mid-tier GPU would be fine, and there are some very cheap options on the used market in most locations.

sproutedpup​ what happened to your old PC? did it have a graphics card in?

my old pc was 120 on amazon. i think that says enough LOL. integrated graphics, barely any storage, etc etc. 

i uh. dont have one near me. i live in a small town and id have to ship it out but none are even close (6 hour drive away) and canada post has been iffy with packages lately, so i dont even know when id get it back. there used to be a guy who did them in my town, so ill see if hes still around before i spend anything.

as for graphics cards, my paychecks are usually 600-700 cad so somewhere around 350-400 cad would be awesome. used are completely fine, as long as the seller has decent reviews! 

sproutedpup​  Looking at sold items on Ebay Canada, you could, if you're paying attention, find any one of these GPUs for under $200 CAD:

AMD RX 6500 XT (about equal to the 580) [January 2022]
AMD RX 6600 standard or XT or 6700 standard or XT (a lot faster) [various dates in 2021]
Nvidia RTX 3050 regular or Ti (somewhat faster) [January 2022]
Nvidia RTX 3060 regular or Ti (a lot faster) [December 2020]

The 6700 regular and XT use a bit more power than the RX 580, but a 650W power supply would be more than fine, and you could get away with 550, or possibly 600 for an overclocked 6700 XT.  The same goes for the 3060 ti.  The other cards use the same amount of power as the 580 or less.  You can see the wattage printed on the side of the PSU.

I put the dates there to give you an idea of how old the model is, although you should keep in mind that individual cards may be newer, as it took a couple years for each to be superceded by the equivalent of the next generation.  Whether you want a newer GPU may depend on how long you plan on keeping this computer, which might be for a while if all you want to play is Sims 4.  While some graphics cards last a decade, I think seven years from initial install is a good estimate of what you can expect.

Local sellers may be able to do even better on price, especially if you have cash and will meet in person.  (For safety, somewhere with lots of security cameras works great, like a Best Buy or a chain pharmacy... or I've heard of people meeting at a police station.  Seriously.)  The fact that you're in a small town can work against you in terms of selection, but it can also help you since sellers won't have as many local options.  And not having to ship the GPU is always a bonus.

If you'd rather not go through this whole process, you can get an RTX 3050 new from Canada Computers for $260, so no worrying about the seller or the condition of the GPU.

https://www.canadacomputers.com/en/powered-by-nvidia/267678/gigabyte-geforce-rtx-3050-windforce-oc-v2-6g-graphics-card-gv-n3050wf2ocv2-6gd.html

"Oof, yeah that sounds like a GPU issue or power supply problem—especially if your entire PC shut down and won't display anything now. Definitely check your GPU connections and PSU, and maybe run hardware diagnostics if you can boot up again. If your USB hub also died, could be a power delivery or motherboard issue too. Hope you can get it sorted! 🛠️💻"

sproutedpup​  Sounds about right.  Let me know if you need anything further from me.