I have a system running dual opteron 248 processors. The server is very very busy during peak times often running at load averages above 3.0 and cpu usage at around 80%+ The system is running with 4gb of RAM currently however we are looking to double that to 8gb and potentially upgrade the CPUs to dual core in the near future.

What I would like to know if I would expect to see a performance improvement if i started to use the x86-64 builds of MySQL rather than the i386 versions. In our lab we have a similar system with less ram and it appear to be faster on the x86-64 builds however its hard to tell until I put it into the real environment. Has anyone got experience of that? they could share.