Depends what your doing on it, and how far you want to push it. GTX x50 cards or 'poor man' graphic cards to make a PC play 'like a console' but NOT like you see on Youtube, Twitch, etc. AKA it doesn't support HIGH/ULTRA 1080P-4K Gaming for Fallout4 or such.
8GB is the MINIMUM for current gaming, considering 4GB can be eaten up just with a 'normal Windows' of just surfing multiple webpages / tabs open, running streaming music, checking your Email in the background, Skype open, etc. most 'common' younger people expect to do 'normally' then add in a Game, well your toast. Most go up to 16GB normally these days, especially if they MULTITASK alot (as I mentioned).
As I mentioned in another thread, "Not sure how familiar your with beyond hardware, but hardware alone (tossing a whole lot of money and buying the most expensive parts) does NOT ensure you will NOT have any type of lag or stuttering. Easily a $4K system can have plenty (of bottleneck) if you don't weekly / monthly maintenance it (running Malware scans, dusting it out, installing driver and software updates by hand, etc.) AND if you SHARE your Internet connection with ANY other devices.
Pure PRO GAMERS get a dedicated Internet connection just to and ONLY for their gaming rigs. They may set up game servers on it, but NO ONE ELSE is using their Tablet on the connection to watch Walking Dead, Sister isn't uploading to her Instagram account, Roommate isn't downloading the entire RubyRose series off Torrent, etc. "