Latency Between Amazon Database Server and Web Server Box

_x000D_ _x000D_ I am setting up a Magento website with a dedicated box from a major web hosting shop (GoDaddy, HostGator, etc...). I'll be using Amazon EC2 or RDS for database hosting for easy scale up. From what I've read, RDS seems to be the preferred choice because of the lower amount of maintenance and administration required. Will there be a noticeable latency difference between the web server and database server if I host one on Amazon and the other on a different provider? The servers will be in the same geographic region, but I assume it must be significantly faster if both servers were hosted on the same cluster at a provider. I've thought about hosting the website on EC2, but would like traditional root access to my box. I also read that a dedicated box is faster than EC2 when it comes to performance. Is this true? This will be a standard e-commerce site; so high number of reads on the DB with much lesser writes to the DB.