Before purchasing any Nvidia card, be sure to go to Wikipedia to see what
chipset is the card based on. For example, you can search for pages named
something like "Nvidia GeForce 700 Series" (However, I can't do this for you,
because Wikipedia has been completely censored in China one year ago.)
You'll see code numbers like GK104 or GM208. The second letter F, K, M, P
denotes Fermi, Kepler, Maxwell, Pascal, etc., i.e. the architecture. The
third digit 1 or 2 means generation under the same architecture. e.g. GM107
is the first generation of Maxwell card and GM208 is the second generation.
The last digit, usually 4 to 8 denotes the performance specification. The
smaller, the higher-end the card is, so GK104 is much more powerful than
GK107.
For freedom's sake, don't purchase 2nd generation Maxwell cards or anything
newer. They require signed firmware and therefore are extremely hostile to
free software. If you want to purchase a high-end GTX780Ti, make sure that
it's NOT a GM2xx. Acceptable cards include GFxxx, GKxxx and GM1xx (but not
GM2xx).
