Quad opteron performance issues in suse 9

I've been playing around with Suse 9 AMD64 for the past few days, trying some canned benchmarks and one that we've constructed. So far, I'm not seeing any scaling from a dual opteron to a quad opteron on suse 9. Most of the tests I've tried are based off of mysql. During the quad cpu tests each cpu was averaging at least 90%, same as the dual cpu tests. Is the 2.4 kernel ok for quad opterons, or is 2.6 required? A side issue, for some reason you cannot install the rpm binaries of mysql 4.0.17 without getting a segmentation fault. So all of the mysql testing was done on 4.0.15, included with suse 9. Cheers