P5b-vm E4300

To lock the multiplier turn off speed step or EIST. 2.8 3.0 ghz is achievable on the right board the board you are using is really quite old and might not be able to handle too much over 1066mhz.

Read the guide in this section about overclocking Core 2 Duos and Quads you might be being held back by your ram or you might need some more voltage either way read the guide.

I managed to disable speed step,but everest still shows x6 cpu´s multiplier.Sometimes it goes to x9,then x6 again,so I just can get 1320 Mhz (220 FSBx6)

I¨ll read the guide anyway to see if I can find anything usefull.

thanks

Next stop should be a guide for your particular motherboard. Google is your friend. And why reinvent the wheel?

I suspect that you are overclocking your RAM and that's limiting your CPU overclock. That's what the next paragraph is for:
Go through the guides. Then take your core voltage off Auto and set your memory voltage to factory recommended values. Change the System Memory Multiplier (or whatever your BIOS calls it) from AUTO to 2.00, 2.00B, or 2.00D - whichever you need to set the Memory Frequency to twice the FSB. Then when you increase the FSB, the memory clock will rise in in proportion with it. At an FSB of 266 MHz, your memory clock should be at 533 MHz.

Download CPU-Z to check your FSB:RAM ratio. It should be a 1:1 ratio.