Confusing HP ML350 G5 and what CPU upgrades are possible?

[JediFonger]

ML350 G5 P/N 419521-005
ML350 G5 P/N 470064-837

i have both of those and it appears as though 419521-005's max is Xeon 53xx series quadcore processors and 470064-837 can take Xeon 54xx.

i know that ML350 G5s lasted through multiple generations of Xeon.

how can i tell for sure which max quadcore i can use with which one?

it appears both have 5000z chipsets