Maybe I begin to understand. In the official spec page there's this line:

*1333 / 1066 / 800 / 533 MHz
(*1333 MHz when overclocking)
2 x DIMM, max. 4GB, DDR2 667/533 MHz

So I suspect it has an old chipset (?) by the way the "945GC(A2) / ICH7"
and the maximun officlal freqs maybe where up to 2,67Ghz and 667Mhz beside "overclocking".

Am I right?

The original 945GC chipset supports 800MHz CPU FSB and DDR2-667. I'm not sure what the 945GC "A2" is as the Intel site doesn't seem to document it, but it apparently can support 1066MHz FSB, as seen on this Asus MB and some ASRock ones. 1066 on 10x multiplier (266 x 10) equals 2.66GHz, so the board was likely respecting your E8600's multiplier setting but was defaulting to a non-OC'ed FSB. So, yes, E8600 @ 2.66GHz and RAM @ 667MHz are the maximum stock values for your setup on this MB.

Thanks, still it seems to run fine at overclocked 3,33 and not really clear PC2-667 or 833 freqs.

386SX wrote:

Thanks, still it seems to run fine at overclocked 3,33 and not really clear PC2-667 or 833 freqs.

1) You need 1333MHz FSB for CPU to be stock clocked.
1333MHz = 333MHz (effective => real). "Real" 333MHz = 667MHz minimum memory effective clock.
Boards that don't support 1333MHz "out of the box", often have "*" near it, along with adnotation "OC".
It means, you have to manually set FSB to higher value.

2) As for RAM, your current setting is in "Memory" tab of CPU-z.
It's a real frequency, so 333MHz in CPU-z = 667MHz in effective value (or what marketing guys use).
Under "SPD" tab, you can see compatibility table with all settings at which your RAM module can work.