When i try to simulate a PCIE example design the simulation time is very large. How can it be optimized to reduce the simulation time

The problem with the Starter edition is not the simulation speed (close to 40% of PE/DE) but the instance limit, if you hit this limit (which I suspect you do with a PCIe core) your simulation speed will effectively grind to a halt (1% of PE/DE speed). You should get a warning that you have hit this limit, if not check your simulation speed (using the simstats command) and the beginning and end of your simulation, you should see quite a difference.

As KTan9 mentioned you need to purchase either the Intel-Modelsim version or the full PE/DE version from Mentor which is not cheap but does not have any speed restrictions and comes with a lot of other goodies such as code coverage. Modelsim DE has (amongst others) full assertion support which can be used for functional verification.

Good luck,

Hans.