OS desicion

Hi List,

I have a Dual-Xeon 3Ghz System with with GB RAM and an Adaptec 212ß SCSI
RAID with 4 SCA Harddiscs. Our customer wants to have the Machine tuned
for best Database performance. Which OS should we used? We are tending
between Linux 2.6 or FreeBSD. The Database Size is 5GB and ascending.
Most SQL-Queries are Selects, the Tablesizes are beetween 300k and up to
10 MB. I've read the Hardware Performance Guide and the result was to
take FreeBSD in the Decision too :)

And what is on this Context Switiching Bug i have read in the Archive? 

Hope you can help me

Regards

Tom