805 Overclocking problems

[nitram]

I have an intel 805 and normally i arrived to overclok it at a stable 3Ghz with stock coolign and maybe at most 3.2Ghz and always got excellent results. now i upgraded to water cooling and tried to overclock it more i increased slightly the voltage to get stable operation. now i reached a stable operation at 4Ghz and ram i trid varies 667,733,750 but i keep on getting a miserable 3300 in pc mark cpu :S when before at 2.66Ghz and at 3 Ghz i used to get some 4200 and 5000 repectively i really dont know where the problem is. i know that if the cpu is hot intel thermal control 1 will stop some cycles to control cpu heat but the cpu is very cool so i must suppse that the thermal control function isnt in operation. i also continueed to raise the voltage but still got no results. i really dont knwo what to do and so i am trying to ask you to check if some one knwos anythign pls. thanks

 

[Arexcedian]

What are your system specs?

 

[nitram]

Evga Nforce680i SLi
7300LE
Raptor 10krpm 74GB
enermax liberty PSU
X-Fi sound blaster
Intel pentium D 805 2.667 @ 4Ghz
1GB kingston ram 533Mhz @ 800Mhz with higher voltages ang latancies highered to support the new frequency