Is 4gb of ram enough for these games?

Global counter strike, apb reload, minecraft, team fortress 2

Yes.

No! I have CS GO, APB Reloaded and Minecraft and I've tested them on a PC with both 4GB of ram and 8GB and I have to say 8GB is a big improvement. Don't be stingy with your money, if you're going to upgrade then go for the better way not the cheap alternative. Minecraft especially likes to have more RAM. For PCs intended for gaming, they should really have a minimum of 8GB RAM. If not able to reach 8GB then 6GB. If not able to reach 6GB then buy a new PC.