Additional memory slowing pc?

Just bought a lenovo m91p tower with/i7processor/4gb/win7 pro 64-bit. I bought an additional 12 gb. Of compatible ram (crucial sys scanner).
working with 1gig dbases; found no time diff for queries that run up to 3 minutes. However, when i ran a query by "name" with 5 additional fields of data>> runtime with 4gb took 1.5 hrs while runtime with 16gb ran 6 hrs. Possible causes and solutions?
More about: additional memory slowing

Unlikely that the additional RAM is the issue. That sounds more like an index issue within the database itself.

Yes