I'm a sound engineer at a Dolby. The power supply could definitely not be the problem. You are better off replacing your monitor so you can check the signal to noise ratio. Use a program like VLC for this.
As long as your gigabytes dont exceed 4GB then your gigabytes should be fine, and all your data would be safe. To be honest its a huge misunderstanding and a myth that you need more than 2GB for gaming, 2GB of VRAM should be fine for any 1080p gaming unless you are trying to run something...