difference with dsp farms

[industryho]

i recently had a dsp farm that i had bought with my pt24 stolen and am looking for a replacement,is there any difference with the pci 3 dsp farms and the pt24 dsp farms and what should i look for when buying(revision),
when i added the pt24 dsp farm to my mix plus setup it gave me 8 additional renaissance comps on a 24 channel session,will a pci 3,dsp farm do the same,help please!!!