The floating-point arithmetic performance vastly improved with the 64-bit environment. The Ubuntu 9.04 64-bit results were close even with Mac OS X 10.5.6.
Under SciMark 2.0, the sparse matrix multiplication performance dropped slightly with the newer architecture.
SQLite with Ubuntu x86_64 continued to struggle compared to Mac OS X. However, as we mentioned in the article last week, there is a nasty regression within the Linux kernel that was not fixed until Linux 2.6.29, where as Ubuntu 9.04 shipped with Linux 2.6.28.