overclocking problem w/ 1.8A on P4S533....

[df1603]

have 1.8A on asus P4S533 with Samsung PC2700 and bios allows me to change fsb/pci up to 133/35 and cpu ratio up to 4:5. If I want to get beyond 133 the system won't start and I get a black screen...
am I doing something wrong or is this just the limitation of my componenets...
anything else I need to change in the bios to make it work @ 150/37?
shall I modify Vcore voltage.

I am new to o/c so need all you help.

 

[Black_Cat]

You might want to try increasing the RAM voltage.

To start press any key. Where's the "any" key? --Homer Simpson.

 

[df1603]

ram voltage?
you mean change jumpers on mobo?
I am new to o/c, so what exactly would you recommend?