What Video Card do you have? I have learned that RCT3 really pushes most video accelerators to their limits because of its extremely realistic graphics. So the bigger your park is, the more objects, models and polygons there are for your video device to process. If you have too big a park, there will be too many for your computer to calculate at once, and lag will occur. Unless you have a very high end graphics card, this will always be a problem.

Try lowering your graphics seetings for more speed.

What Video Card do you have? I have learned that RCT3 really pushes most video accelerators to their limits because of its extremely realistic graphics. So the bigger your park is, the more objects, models and polygons there are for your video device to process. If you have too big a park, there will be too many for your computer to calculate at once, and lag will occur. Unless you have a very high end graphics card, this will always be a problem.

Try lowering your graphics seetings for more speed.

NVIDIA GeForce 9400 GT (Microsoft Corporation - WDMM v1.1)

Thats my video card.

How long have you had your computer?

1 year because now we setup and bought new CPUs, motherboards, fans, etc

Yeah, that is a good card up to point. Belive it or not, a GeForce 8800 GT or GTS is faster then any of the 9000 cards!