Hello, I have a Dell XPS M1730 Red laptop!

I'm just curious if you guys think this pc is good enough for HD video editing?.
When i put my mts files on Sony vegas with this program it gets really laggy and I dont know why ? is there any ways to avoid this problem ?

Info of my computer!
Intel Core 2 Extreme 2.8GHz (Overclockable via BIOs to 3.4GHz),
4GB Shared Dual Channel DDR2 SDRAM,
2x200GB 7200RPM Hard Disk In RAID 0,
Dual NVIDIA SLI GeForce 8700MGT,
AGEIA PhysX 100M Processor,
Blu-ray Disc Combo (DVD+/-RW)
17" WUXGA Display with built in 2MP Camera and Mic.