Lagging when live streaming

[xACR33Dx]

Whenever I live stream I lag in-game, I am using Open Broadcaster Software and I have set the bitrate to 3200kbps and buffer size to 3200kbit (is that too much?).

My PC specs are
Intel Core i5 2400
GTX 550TI
8GB DDr3 1333mhz
1TB SATA 6gb 7200RPM 32MB Cache
1600x900

Does live streaming affect the hard drive or processor the most or am I running out of ram?

My internet speeds from speedtest.net are

Ping: 10ms
Download Speed: 34mbps
Upload Speed: 23mbps

Why do I lag when I go in a game on Black Ops 2?