32 en 64bit hangt af van de CPU die je hebt in die pc, die bepaalt of 64 bit kan of niet.
als het een 32bit cpu is kan je geen 64bit installeren.
Server 2008 R2 is radically different from Server 2008. There are MANY kernel changes, especially in the area of power management (core parking for one) and the ability to handle (with the appropriate version) 256 Processor Cores.
R2 provides a way of saying "Your CALs are still good". With R2, you buy the SAME CALs (the CALs don't need to be upgraded) that you did with the original version.
It's not a psychological thing at all. It's called R2 because it's a different kernel version (and build) from 2008. Server 2008 uses the 6.0 kernel (build 6001), 2008 R2 uses the 6.1 kernel (7600). See the chart on wikipedia.
R2 is a better way of describing it because the services packs don't change the kernel (to my knowledge) but R2 isn't exactly that much newer as a completely new version. The difference between Windows Server 2003 and 2008 are huge, but changing the kernel won't typically be obvious to users as it's an internal change within the OS. There's seldom real new tools, interfaces or features with an "Rn" label. It's just an upgraded core where as newer versions have newer core with additional feature and tools.
For Windows 2008 R2, according to wikipedia: "Version enhancements include new functionality for Active Directory, new Virtualization and Management features, the release of IIS 7.5, and support for up to 256 logical processors."
een tabel met de windows versies:
Comparison of Microsoft Windows versions - Wikipedia, the free encyclopedia
oa windows server 2008 en 2008 r2