ASUS P5VDC-X possible to have 4GB Memory

Your MB chipset will work with 2 GB. memory max. 2 x 2 GB DDR2 DIMMS may possibly boot, but the MB chipset is limited to 'working' with a maximum of 2 Gbs of memory, either DDR or DDR2. 2x2 GB would be of no use with the chipset you have.

The company who lists the 2 x 2 GB kit doesn't even mention the name of the RAM Mfg?

Here's Crucial's recommendation:

http://crucial.com/store/listparts.aspx?model=P5VDC-X

ASUS P5VDC-X product page specs:

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)

Well, there are a lot of socket 775 MBs that would handle 4 GB or more of DDR2 the latest chipsets you would look for are the Intel P35 and X38. AMD's latest would be the 780/790i chipsets. You would need a 64 bit operating system to fully utalize 4 GB of physical RAM. Windows XP 32 is limited to 4 GB, but depending on what hardware your system is composed of (video card, etc) only a portion of that 4 GB will be designated by the OS to the system hardware you are running.

I currently have the following socket 775 MBs running, all chipsets will support 4 Gb RAM or more :

Intel X38
P965
Q965
945

P35 or x38, take your pick and preference of manufacturers. ASUs is good. Gigabyte, Abit too.

Prob go with an Asus as thats what i got already. is it a simple switchover? Any hardware conflicts to be aware of?

yes, that was the whole problem when this mobo was installed. looks like the power mac awaits ....rather than rejog the whole system. we'll see....