HP Workstation xw4600
Intel Core 2 Quad, 2.4Ghz
0AA0h HP Motherboard
ATI Radeon HD 5670 (upgrading soon)
and currently RAM is
4 x 1GB ECC DDR2 @ 400Mhz.
Now I'd like to upgrade the RAM to at least 8GB, possibly 16GB if the price is right. I assume just buying 4x2GB or 4x4GB versions of the cards I already own would be sufficient, however the official support document (http://h18000.www1.hp.com/products/quickspecs/12792_na/...) for the workstation only lists PC2-6400 DDR2-800 as compatible. Whenever I search this type of memory it is not only more expensive but always classed as server memory!
Now all listings stress that it's server memory and won't work in normal desktop PC's, but seeing as my workstation says it supports it, is server memory okay for me?
What has caught my eye is some RAM online with the details: 'PC2-3200R DDR2 ECC Registered Server Memory'. will this work? It's 400Mhz and not 800Mhz as the pdf states, and it also PC2-3200 and not the desired PC2-6400.
DDR2 RAM is becoming obsolete (kinda' already is). Server RAM often works at 2.5v and higher so you would need to up the voltage from the mobo to be able to use it (as far as I can tell, also your motherboard does not have that feature). You would notice the difference in speed going from 800MHz to 400 without a doubt, to the point where it may not even be worthwhile to "upgrade". I say upgrade in quotation because it would be more of a sideways move. Trading more space for half the speed.
There is nothing wrong with your system (although it is dated). If you are considering upgrades it may be a more viable (availability and price wise) choice to start looking at a new PC
P.S. Whenever you are looking at something reporting the speed of the RAM remember: DDR2 400 = "2" x 400 = 800MHz
Thanks for the help, I only recently got the PC so ideally don't want to be getting a whole new setup just yet. Going to put in a better power supply I have (500W) and upgrade from '4x1GB ECC DDR2-3200 400Mhz' to '2x4GB ECC DDR2-6400 800Mhz'.