[alexisl]

I have a p5 570 with 8 2-way processors and 19,456 MB of RAM. We are going to do a memory upgrade of 4 GB (8 512 MB DIMMs). As I was reading the "Redpaper" IBM e server p5 570 Technical Overview and Introduction I read a note in paragraph 2.3.1 (page 26) that says "A quad must consist of a single feature (that is, made of four indentical DIMMs)."

Does that mean that I must put 4 of the new DIMMs on each processor card or can I divide them among the 8 cards?

If I have to put all the memory upgrade onto 2 cards what effect will that have on the system?

[3geofftech]

You can divide them across your processor cards providing you do so in quads (4 identical dimms) as per the rules and slot locations which you'll find in the redbook.
Balancing memory across cards is generally better than lumoping them all together.