The first two columns are the signature used to identify the card.
The third column indicates the brand - 1 for ATI/AMD, 2 for NVIDIA.
The fourth column indicates the capabilities of the processor on the card. These are brand specific from what I've read elsewhere on the forum. Higher values are better, but I don't know what the threshold is for a card to be supported - again that seems to vary between NVIDIA & AMD.
The last column is just a text identifier.
If I want to know whether a GPU is supported by F@H, I just go look it up in the
TechPowerUp GPU database. If the card supports OpenCL 1.2 and 64 bit floating point, it should be able to fold; if it's missing either of those things, it won't.