桌電玩lol好LAG= ="請問能幫我看一下是哪裡不足嗎?

CPU
2.5 GHz Performance Rated at: 5.5 GHz
RAM
2.1 GB
OS
Microsoft Windows 7 Home Premium Edition (build 7600), 64-bit
Video Card
GeForce G100
Free Disk Space
268.1 GB

特效都調到最低了,但還是會lag,尤其會戰大家放技能時~"~根本不會動...3秒後直接黑白畫面
請問哪裡不足?