Abit IS7 and DDR not up to speed

Hi,
I've also posted this in the memory portion of the forum but in case it is a board problem.. I recently built the following system:
Abit IS7
2.4C
Kingston Hyperx 4000 2/512 (DDR500)
Antec truepower 380 Watt
older NVIDIA bloody monster (440mx) video card
plextor cd R/w
Maxtor 40 Gb HD
The system runs fine at 250 mhz FSB ( 3.006 Ghz) but ONLY if memory is at 5:4. I have bumped the Vdimm from 2.6 to the max 2.8 volts and i get longgggg beeps if i am trying the 1:1 ratio. The cpu push has been an easy one. Default voltage. and temps under load barely exceed 51C with stock sink and fan. However, even after RMA of the memory the new kit does exactly the same. Is it my supply? Kingston tech support said 430 watts may be necissary. I had not heard of this before. The behavior does'nt seem consistant with a bad supply.
Any thoughts would be appreciated.

first of all u might want to read yourself through this:
http://forum.abit-usa.com/showthread.php?s=&postid=179923#post179923

As yourself, I thought my PSU is too small so I switched to an Antec True Power 450 - nothing changed. However it was not a bad move

Thanx mihocu. I have continued to work the problem. Sometimes i get no beeps and system does re-boot itself. Sometimes longggg beeps.