It is not possible to answer the question of why some particular element of a game is laggy without reading the source code. So you will not get it in community driven forum.
All we know is that the game has a memory leak that causes it to slow down after a few matches. Everybody seems to get over it and restarts the game after every second match.
Mind that with your equipment, it is very unlikely that improving the hardware will change this. You just need to restart. It is that simple and it is the only thing you can do.
Okay I see. Thanks anyway
Relic Entertainment
cblanco ★ 
보드카 중대 
VonManteuffel 
Heartless Jäger 
