ProxyCreationEnabled in Entity framework

Hi

I read about ProxyCreationEnabled in the link.. https://stackoverflow.com/questions/4596371/what-are-the-downsides-to-turning-off-proxycreationenabled-for-ctp5-of-ef-code-f

I Know that it create proxys of entities but I don't know if ProxyCreationEnabled = true is slow.

I have the configuration:

Configuration.AutoDetectChangesEnabled = true;
Configuration.ProxyCreationEnabled = false;
Configuration.LazyLoadingEnabled = false;

I would like to know if ProxyCreationEnabled = true doesn't create problems with performance and the effect in my configuration.