Low perf of i386 6.0 on dell poweredge 1850 bi-Xeon 2.8ghz DualCore

[Eric D'HEM]

Mail NETvigieHi,

I buy a new DELL PowerEdge 1850 with Bi-Xeon 2.8GHZ/2*2MB Dual Core 800FSB 
processor, 2Go DDR2 RAM, PERC4di RAID controller with 2 SCSI U320 15.000tpm 
36Go hdd on RAID1.

I install on it Freebsd 6.0, apache 2.2.0 and mysql 4.1.18 and compare 
performance with :

OLD PowerEDge with only simple Bi-Xeon 3.0 GHZ and freebsd 4.11.

Result is that web and local databases query are +- 4 times slower with 
freebsd 6.0 and dual-core.

I try with and without smp and  threaded kernel and results are same.
I came back to Generic kernel to see if it come from my kernel configuration 
but result was same.

I then think it come from hardware configuration, call DELL, then I change 
lots of settings but result was same.

I then try to install a slackware distribution and have really good 
performances.

Do you have any idea?
Do you think 6.1 release will be ok?

N.B : I run ubench tests but I don't think result is significative