what is the different between this cpu :

GenuineIntel
Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz [x86 Family 6 Model 23 Stepping 10]
(2 processors)

and

GenuineIntel
Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz [x86 Family 6 Model 23 Stepping 6]

I got this from collatz page, there is something different also on other page.

Click on the FIRST result from this search ....

http://lmgtfy.com/?q=define+cpu+core+stepping+for+intel

hmm.... there is two kind of E8400 never thought of that.

SLB9J 3 GHz E8400 2 1333 MHz 45 nm E0 6 MB LGA775 06
SLAPL 3 GHz E8400 2 1333 MHz 45 nm C0 6 MB LGA775 06

wonder which one is the best for boinc.

The difference in application performance is probably minimal, but there could be differences in other factors like operating temperature, etc.