Your (basic specs) isn't a problem.
What kind of internetconnection are you using? in case of wifi, did you try plugging into the router directly? What is the ping (coloured dot) telling you (default position is to the lower right corner, when mousover you get some details bout framerate etc.).
*In my opinion it can be two problems.
a: graphic card related problem (faulty hardware or a driverissue). I have a 10 year old laptop wich does what you are describing (extually i can stand in my GH as long as none fireworks are going off and it's void of people, then I get the bouncy freezing thing. I use it for sometimes for chatting with people). But those specs are way below the minimal requirements.
b: routing issue. keep in mind with routing I'm not talking bout your home router alone, but bout all steps needed to have a connection from the gameserver to your computer. most of the time this is an issue with your home router (where some ports are being blocked) or with your internet provider. Some ways to troubleshoot this is giving more info here bout your country, your internetprovider, your home-network (like brand of router) etc.