To take advantage of a dual core, you must use BOINC. As you asked this question in the BOINC forum, can I assume you already are?

If you are using the UD client instead, then it's easy enough to migrate.

Hello Wilgard,
BOINC can run 2 applications on a dual core, just as though you had 2 computers sitting side by side. Just remember that this will take twice as much memory and twice as much virtual memory.

BOINC decides how many work units to download based on how often you tell it to communicate. The default is to communicate every 0.1 days (2 hours and 24 minutes). This will cause it to keep an extra work unit on hand (2 for a dual core) to make sure it continues crunching during the communication delay period. If instead you change the BOINC profile to communicate after 0.5 days, then it will cache enough work units to stay busy for half a day. There are potential scheduling issues if you tell it to draw enough work units for several days. At the least, you will slow down the validation of results for other people.

Lawrence