I'm not sure of your hardware. We have a Dell PowerEdge 2900 for our Primary server and the upgrade from Prinergy 5.1 to 5.2 did not require a hardware upgrade but we did have to upgrade the OS from 32-bit Windows Server 2003 to 64-bit Windows Server 2008 and the requirements for ram went from 4 gb minimum to 8 gb minimum. We went ahead and jumped up to 20 gb of ram. The main reason we needed to upgrade is that there were known issues using Preps 6 with Prinergy 5.1.x and the only fix for that is to upgrade to Prinergy 5.2.x.
Prinergy 6 is in development and they say will be available in 2013. They are supposedly showing it at Graph Expo next month.
OS: Mac OS 10.8.4 - RIP: Prinergy Connect 5.3 - CTP: Luscher XPose! 160 (2)