System statistics.. any advice ?

Hi,
I'm looking for any advices, recommandations, experience with system statisitics. I'm making a lot of test on 10g database (10.2.0.3) on RAC and stand-alone instance.

On a RAC, I get these stats with a WORKLOAD gathering type:

PNAME                                 PVAL1
------------------------------ ------------
CPUSPEEDNW                          437.129
IOSEEKTIM                                10
IOTFRSPEED                             4096
SREADTIM                              5.212
MREADTIM                             10.553
CPUSPEED                                446
MBRC                                     18
MAXTHR                               224256
SLAVETHR

And, with a NOWORKLOAD gathering type :

PNAME                                 PVAL1
------------------------------ ------------
CPUSPEEDNW                          437.133
IOSEEKTIM                             6.647
IOTFRSPEED                        26003.733
SREADTIM
MREADTIM
CPUSPEED
MBRC
MAXTHR
SLAVETHR

On each node, i have 6 processors except one node that it have 8 processors. All processors operates at 900 MHz each.

In both situation, CPU statistics are lower than I expected.