Jayz2Cents is here to the rescue. He first explains what those 8 – 12 manufacturers of graphics card do to those cards and then gives us details about what matters. Most often than not, some manufacturers will choose to add a ton of features to the base graphics cards someone like Nvidia prints specs out for.
Nvidia gives out the specs, but manufacturers are free to add whatever they want. This is why you see that the video cards may have different fans or different VRAM.
Now, to what matters: the amount of VRAM the cards nowadays have is typically 2GB, but you may need more if you have monitors that run above 1080p. MSAA might consume large amounts of VRAM but you woudl not need it if you run even at 1080p.
Usually when its about graphics cards I look for these things:
– GPU – the more the better, needs to be above 1GHz
– VRAM – it needs to be GDDR5 and at least 3-4 GB
– bits – usually you will find with 128 bit BUSes, but I’d choose those with 512 bit
A card like the one from above would cost easily above 500 USD, but it makes magic.