Problem with Java1.x/JDBC:OCI on solaris 8 64-bit?

Hello. This is my first post, so try to keep the flames down

We recently upgraded our Sun SPARC machine form solaris 7 to solaris 8. In the process, we decided that it wouldn't hurt to try the 64-bit instead of 32-bit kernal.
Well, now our nightly java batch processing has gone from taking 4 hours to 7.5!
We've narrowed it down these main possibilities for a cause:
Solaris 8: maybe they screwed something up in this release?
64-bit: problems with Java and 64-bit? like garbage collection maybe? More memory overhead?
An install error for the OS: that would fall under the "not our fault" category

JDBC Interaction with 5.8 OS?
JVM Interaction with 5.8 OS?
Any ideas you have would be appreciated!