Short answer after testing it my self is, it works!
After update and upgrade start raspi-config and update this.
I could not get the 1Ghz to work but I got "high mode" (950Mhz) working!
How did I check this worked? I installed nbench from http://www.tux.org/~mayer/linux/bmark.html and run ./bench in the unpacked catalog.
My values might have been kind of low because I run under Xwin.
Got this:
=====================ORIGINAL BYTEMARK RESULTS=====================
INTEGER INDEX : 15.668
FLOATING-POINT INDEX: 5.021
Baseline (MSDOS*) : Pentium* 90, 256 KB L2-cache, ...
=========================LINUX DATA BELOW==========================
CPU :
L2 Cache :
OS : Linux 3.2.27+
C compiler : gcc version 4.6.3 (Debian 4.6.3-8+rpi1)
libc : libc-2.13.so
MEMORY INDEX : 3.442
INTEGER INDEX : 4.302
FLOATING-POINT INDEX: 2.780
Baseline (LINUX) : AMD K6/233*, 512 KB L2-cache, gcc 2.7.2.3, ..