Does this actually work? I'm building a PC myself and I already have a case, but if this is true, is it possible to build one without a case? I'm just curious because I'm a beginner myself.
You don't even need a cardboard box, just put everything on the desk. Not recommended, but it works.
A lot of the PC sites/Youtube channels use test benches like these. It is exactly what it looks like.
One important difference between dumping everything on the desk and the setup above is that they have support for the PCI-E card so they don't wobble in the slot, slowly creaking and cracking both the slot and themselves.
Is there a solution to this potential problem that you could recommend? Right now it's running fine but it hasn't been very long since adding the GPU.
Is it possible to get a larger case and transfer everything to it?
Or would I have to just buy a bigger case, new motherboard and CPU, and transfer the power supply, GPU, and hard drives to it?
You can download GPU-Z and CPU-Z and monitor the temperatures under heavy load, that way you will know for sure if it hits the thermal limit and throttles, it's a good place to start before spending money. It's probably fine, the 1660 isn't running that hot, but it isn't a bad idea to check.
You could also download Asus GPU TweakII, it works on any card, it has FurMark built in and that program has an interesting history. FurMark is the reason that they implemented thermal throttling. It is often called a power virus because it sends temperatures beyond what a normal application/game could do by hammering a specific set of instruction, it fried cards in the past and people got very pissed.
It's harmless now but it will force temperatures as high as they can go, it is used as a stress test when overclocking.
This means that if running Furmark crashes your card/display driver under stock setting, no overclock, then it is getting too hot in the case, it can't get rid of the heat.