Online dedicated server with quickbox timeout

Hi, I have some scenario with you all.
I have some dedicated server with

My server spec is like this.

Core i3-530
2.9 GHz 2 cores
2× 1 TB (HDD SATA)
Raid 0

I install quickbox, and run about 4 user and my rtorrent keep timeout, and the cpu usage getting high.
I try other script using nginx but no problem happen if run 4 user. rtorrent never timeout and cpu always lows.

Why ya ? Please help me. I love QB so much. Tq.

Is the issue still going on?
Can you shoot us a screen shot of your process log? (top)