Memory upgrade problems

[Nottechsavvy]

Hi, I am attempting to upgrade my memory from 2x1GB PC-4200,to 2x2GB PC4200, and I am experiencing problems.I am running an Asus P5VDC-X motherboard,Pentium 945 D,3.2 GHz,XP Pro.The board features both two DDR slots and two DDR2 slots.When I installed the matched pair of Kingston 2x2GB cards my computer beeped four times and then nothing,(ie.no startup screen or bios message). When I attemped toindividually install either of the two strips in either of the two slots,they worked fine,(system RAM at 2GB).Also installing either of the two 2Gb strips in conjunction with either of my old 1GB strips works fine,(system RAM at 3GB).What can I do to run my motherboard at 4GB??? Any advice at all would be greatly appreciated,
Sincerely, Nottechsavvy.

 

[IH8U]

Voltage is the most likley culprit here, I suggest removing the 2 1GB sticks, and using just the 2 2GB ones. install one, then enter the BIOS and adjust the memory voltage till it equals 2.1V, reboot, then power off and add the other stick.

 

[bobbknight]

I would set the voltage that our motherboard supply's to the ram by what is printed on the ram sticker/or what the ram maker says to set it at in the bios.

 

[outlw6669]

The ASUS P5VDC-X only supports 2Gb of RAM.
It will not work with 4Gb.
Also, you should not use DDR and DDR2 RAM simultaneously.

2 x 240-pin DIMM Sockets support max. 2GB DDR2 533/400 non-ECC, unbuffered memory
2 x 184-pin DIMM Sockets support max. 2GB DDR 400/333/266 non-ECC, unbuffered memory
(Note: DDR and DDR2 memory can not be used simultaneously)

 

[Nottechsavvy]

Thankyou very much for your responses.I have one more question,which voltage setting listed in the bios correlates to memory? (there is no specific "memory voltage" listed. those listed are; VCORE,then 3.3V,5V,and 12V.I am assuming that it is the second listing,3.3V,but I want to be sure .Sorry for my ignorance,and thankyou again for your help.Sincerely, Nottechsavvy.

 

[outlw6669]

None of those settings correspond with the RAM Voltage.
The first is the CPU Voltage and the rest should be giving you readings from your PSU's voltage output.
As you have have in Intel branded motherboard, it is possible that you do not have the ability to change the RAM voltage.
As such, you should probably get a JEDC spec DDR2 800 kit that runs at 5-5-5-18 timings and 1.8v.

Glad to help and do not worries.
We all started off knowing nothing once...