Linked Server performance varies depending on user

Hi

I am having a very strange problem with a linked server query.

I have a query that selects from some local tables and also joins to two
tables on a linked server (on the same SQL server). The linked server is set
to use the login's current security context. If I run the query as an
administrative user, the query takes 10 seconds to return data, however, if
I run the query as a non-administrative user the query takes 1min 3 seconds
(exact same query). I have confirmed that the user has select permissions of
all the objects required and that the result sets are identical.

Has anyone experienced this before? what could be causing this? is there a
solution?

Any help will be greatly appreciated

Thanks
Craig