How can I identify and fix bottlenecks in an Oracle11gR2 import

Question

I've recently been tasked with moving our Oracle 11g database from a linux CentOS desktop to a windows 2008 server. Given I've not done much behind the scenes stuff with oracle before I'm a bit out of my depth.

I did a full expdp from the source server and imported it to the target server (i built tablespaces before the load but nothing else).

Everything went well enough (a few errors that were related to having a different global_name which, from documentation, appeared ignorable.

The problem I am having is that the new server appears to take longer to run queries compared to the old server. This is in spite of more cores and more RAM. I think the problem is due to I/O limitations as the old server ran on an SSD.

I get the same 'explain plans' on queries yet getting through the blocks on v$sql_longops just seems to take longer... Can anyone provide details on what steps to take to check and compare output so I can try to ascertain the underlying issue?