Failing Power Cable

[Eastman51]

So over the past week and half, my GPU stopped functioning at its normal capacity, no longer ran Overwatch at 60fps, various other games also suffered from significant slowdowns and frame variations jumped erratically during some others. About a week ago, I received the fans I had ordered in the mail and installed them, this resulted in temperature decreases on the GPU by 30C (previously ran around 80C). But today, when I decided to get back into Overwatch with some friends, I refused to play at 28fps compared to the smooth, never dropping 60fps of a few weeks earlier. I looked at CPU usage thinking that my CPU was dying, I checked my hard drives and RAM, even tried closing background programs and messing with Nvidia Control Panel to fix the issue, but none of these were the solution. I decided to shutdown my system and take a look inside, maybe a cable was unplugged or I was drawing too much power, hoping my RAM, CPU, and GPU weren't the problem. Turns out I was mostly correct. The CPU, RAM, and GPU are perfectly fine, however, my GPU is not being supplied with enough power. My power supply is perfectly fine, however, since my PSU is an OEM one that came with my PC (pre-upgrades) it doesn't have a 4pin PCIe connector on it. So, in response to this, I bought a Molex to 4pin adapter when I bought my GPU. The installation went smoothly and my GPU worked fine, until that adapter started to fail (about a week and a half ago). I know for a fact that I need to get a new adapter (or PSU I guess, but it isn't NEEDED, so idk), but I don't want to get a cheap, crappy one like I ended up getting (I got my GPU and this adapter in late June, fyi). So, if possible, I'd like some help in finding some good molex to 4pin PCIe adpaters on Amazon. Thanks for the help.

Here's a video showing the cable changing the light on the GPU to red because it can't supply power:

IMG_9929.MOV