I have a three year old Dell 3847 Inspiron (i3-4150) with HD Graphics 4400 (dedicated 128 VRAM). I want to add a very inexpensive graphic card to play basic games. I don't want to make any additional upgrades. I want something that will function with my current standard power supply which I am guessing is 300W. I have been looking at GeForce GTX cards, but am not sure which would run the best. GeForce GTX 550 Ti or a GeForce GT 730? Does the brand matter - PNY vs ASUS vs EVGA? Will it be hard to install? I have never done this before and I saw blogs saying you might have to go into the BIOS, disable secure boot, and enable CSM? I am running Windows 8.1.