Hey, im thinking of getting a second Seagate Barracuda 7200.11 500GB drive for a RAID 0 configuration.
My question is how much this would improve overall performance and loading times of my system.

My setup is:
CPU: Intel Q9450
MB: Asus P5Q-E
RAM: 4GB Corsair XMS2 DHX PC2-6400 (CL4-4-4-12)
GFX: Radeon HD 4850
HDD: Seagate Barracuda 7200.11 500GB
PSU: Corsair 650TX

Thanks in advance.

The booting time will decrease.... well a bit faster I think, but for gaming it just lower the loading time. Still I do get 5 minutes load in Bioshock

Your board has the ICH10R southbidge, it will cook with an added 7200.11 drive.

Ouch, never heard about that. Please tell more.

Reference bobbknight:
Your use of "cook" do you mean smoking Fast ( I doubt). Small performance gain.
Or "cook" as fry/overheat. The ICH10R provides support for up to 6 drives. While I have the older ICH8R southbridge I have 4 HDD's, two pair of raid0, with no problems of overheating.

ICH10R absolutely flies with RAID. It can't improve everything, but as RAID controllers go, it is quite good.