FreeBSD-amd64-RC1 problem on Dual AMD64 with 8GB RAM (IBM @server 325, ServeRAID 6M) and mysql

Hi,

I did binary update from CD and now I'm trying to cvsup for RELENG_5_3 tag.
The reason I got Dual AMD machine is I want to run mysql-4.0.x with default 
threading library and see the performance.
Because we are using mysql on FreeBSD extensively for email server and 
storing email messages to mysql DB.

We have around 10 different x86 machines with FreeBSD 5.x/mysql with 
linuxthreads
and only one FreeBSD (updated on March) with default threading library.
The machine with default threading library is little slower than the one 
with linuxthreads.


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Also "btxld: No such file or directory" problem was solved in following way.
Probably I have to do it again before doing installworld.

make installworld somehow didn't know the paths
of the following tools: btxld, dd, cp, ls. I added full path to following 
Makefiles.

Changed Makefiles files:

/usr/src/sys/boot/i386/boot2/Makefile
/usr/src/sys/boot/i386/loader/Makefile
/usr/src/sys/boot/i386/pxeldr/Makefile
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By the way, when FreeBSD-AMD64 will support more than 4GB of RAM?
Also is there any tips and tricks to compile mysql-4.0.21 with default 
threading library on AMD64 machine?

thanks,

Ganbold